diff --git a/src/consts.rs b/src/consts.rs
index 82685f1..1d57c19 100644
--- a/src/consts.rs
+++ b/src/consts.rs
@@ -7,7 +7,6 @@ use crate::voices::Instrument;
 pub const WINDOW_WIDTH: i32 = 1280;
 pub const WINDOW_HEIGHT: i32 = 720;
 
-pub const BEATS_PER_LOOP: f64 = 16.;
 pub const DEFAULT_BEATS_PER_LOOP: usize = 16;
 
 //
@@ -29,9 +28,6 @@ pub const ALL_INSTRUMENTS: [Instrument; 10] = [
     Instrument::PedalHiHat,
 ];
 
-pub const GRID_ROWS: usize = ALL_INSTRUMENTS.len();
-pub const GRID_COLS: usize = DEFAULT_BEATS_PER_LOOP;
-
 // Message passing (TODO: move to events?)
 
 #[derive(Debug)]
@@ -55,7 +51,7 @@ impl UserHit {
         }
     }
 
-    pub fn beat(&self, beats_per_loop: f64) -> f64 {
-        self.clock_tick % beats_per_loop
+    pub fn beat(&self, beats_per_loop: usize) -> f64 {
+        self.clock_tick % (beats_per_loop as f64)
     }
 }
diff --git a/src/egui_ui.rs b/src/egui_ui.rs
index cd14339..fc6375d 100644
--- a/src/egui_ui.rs
+++ b/src/egui_ui.rs
@@ -11,7 +11,7 @@ use log::info;
 use macroquad::color::{DARKBLUE, GREEN, LIGHTGRAY, ORANGE, PURPLE, RED};
 
 use crate::{
-    consts::{UserHit, ALL_INSTRUMENTS, GRID_COLS, GRID_ROWS},
+    consts::{UserHit, ALL_INSTRUMENTS},
     events::Events,
     score::{
         compute_accuracy_of_single_hit, compute_last_loop_summary,
@@ -21,8 +21,6 @@ use crate::{
     voices::{Instrument, Voices},
 };
 
-pub type EnabledBeats = [[bool; GRID_COLS]; GRID_ROWS];
-
 // This resource holds information about the game:
 pub struct UIState {
     selector_vec: Vec<String>,
@@ -41,8 +39,6 @@ pub struct UIState {
     current_beat: f32,
     beats_per_loop: usize,
 
-    enabled_beats: EnabledBeats,
-
     latency_offset_s: f32,
 
     user_hits: Vec<UserHit>,
@@ -86,8 +82,6 @@ impl Default for UIState {
 
             latency_offset_s: 0.,
 
-            enabled_beats: [[false; GRID_COLS]; GRID_ROWS],
-
             user_hits: vec![],
             desired_hits: Voices::new(),
 
@@ -129,10 +123,6 @@ impl UIState {
         self.current_loop = val;
     }
 
-    pub fn set_enabled_beats(&mut self, voices: &Voices, beats_per_loop: usize) {
-        self.enabled_beats = voices.to_enabled_beats(beats_per_loop);
-    }
-
     pub fn set_bpm(&mut self, bpm: f32) {
         self.bpm = bpm;
     }
@@ -454,31 +444,6 @@ fn draw_central_panel(ctx: &egui::Context, ui_state: &UIState, events: &mut Vec<
 const VIRTUAL_WIDTH: f32 = 800.;
 const VIRTUAL_HEIGHT: f32 = 1000.;
 
-fn is_beat_enabled(
-    visible_row: usize,
-    col: usize,
-    enabled_beats: EnabledBeats,
-    visible_instruments: &[&Instrument],
-) -> bool {
-    // determine instrument
-    let res = visible_instruments
-        .iter()
-        .enumerate()
-        .find(|x| x.0 == visible_row);
-    let ins = match res {
-        Some(x) => *x.1,
-        None => panic!("invalid instrument idx"),
-    };
-
-    // see if it's enabled
-    let res2 = ALL_INSTRUMENTS.iter().enumerate().find(|x| x.1 == ins);
-    let row = match res2 {
-        Some(x) => x.0,
-        None => panic!("invalid instrument idx"),
-    };
-
-    enabled_beats[row][col]
-}
 fn draw_beat_grid(ui_state: &UIState, ui: &mut egui::Ui, events: &mut Vec<Events>) {
     let (response, painter) = ui.allocate_painter(
         egui::Vec2::new(ui.available_width(), ui.available_height()),
@@ -504,7 +469,7 @@ fn draw_beat_grid(ui_state: &UIState, ui: &mut egui::Ui, events: &mut Vec<Events
         ALL_INSTRUMENTS
             .iter()
             .enumerate()
-            .filter(|(idx, _)| ui_state.enabled_beats[*idx].iter().any(|b| *b))
+            .filter(|(_, ins)| !ui_state.desired_hits.get_instrument_beats(ins).is_empty())
             .map(|(_, ins)| ins)
             .collect()
     } else {
@@ -512,7 +477,7 @@ fn draw_beat_grid(ui_state: &UIState, ui: &mut egui::Ui, events: &mut Vec<Events
     };
 
     let visible_rows = visible_instruments.len();
-    let visible_cols = GRID_COLS; // future, this depends on length of loop
+    let visible_cols = ui_state.beats_per_loop;
 
     let width_scale: f32 = VIRTUAL_WIDTH / visible_cols as f32;
     let height_scale: f32 = VIRTUAL_HEIGHT / visible_rows as f32;
@@ -580,7 +545,6 @@ fn draw_beat_grid(ui_state: &UIState, ui: &mut egui::Ui, events: &mut Vec<Events
             continue;
         }
 
-        // draw a horizontal line through the middle
         let base_pos = pos2(0., (visible_row as f32) * height_scale);
         let start_pt = to_screen.transform_pos(base_pos);
         let end_pt =
@@ -606,6 +570,7 @@ fn draw_beat_grid(ui_state: &UIState, ui: &mut egui::Ui, events: &mut Vec<Events
         shapes.push(shape);
     }
 
+    // Draw horizontal lines
     for visible_row in 0..visible_rows {
         // draw a horizontal line through the middle
         let base_pos = pos2(0., (visible_row as f32 + 0.5) * height_scale);
@@ -616,29 +581,25 @@ fn draw_beat_grid(ui_state: &UIState, ui: &mut egui::Ui, events: &mut Vec<Events
             egui::Stroke::new(1., Color32::DARK_GRAY),
         );
         shapes.push(shape);
+    }
 
-        // TODO: Instead of looking at each potential beat, draw the beats where it says they exist!
-        for col in 0..visible_cols {
-            let t_rect = rect_for_col_row(col, visible_row, to_screen, width_scale, height_scale);
-
-            // if this beat is enabled (row is instrument, col is beat)..
-            if is_beat_enabled(
-                visible_row,
-                col,
-                ui_state.enabled_beats,
-                &visible_instruments,
-            ) {
-                // TODO: These are being drawn over by `draw_note_successes`. how to handle?
-                let shape =
-                    egui::Shape::rect_filled(t_rect, egui::Rounding::default(), beat_fill_color);
-                shapes.push(shape)
-            }
+    for (visible_row, ins) in visible_instruments.iter().enumerate().take(visible_rows) {
+        let desired_hits = ui_state.desired_hits.get_instrument_beats(ins);
+        for d in desired_hits {
+            let t_rect = rect_for_col_row(*d, visible_row, to_screen, width_scale, height_scale);
+            let shape =
+                egui::Shape::rect_filled(t_rect, egui::Rounding::default(), beat_fill_color);
+            shapes.push(shape)
         }
     }
 
     // Draw Note Successes
     let loop_last_completed_beat = ui_state.current_beat - MISS_MARGIN as f32;
-    let current_loop_hits = get_hits_from_nth_loop(&ui_state.user_hits, ui_state.current_loop);
+    let current_loop_hits = get_hits_from_nth_loop(
+        &ui_state.user_hits,
+        ui_state.current_loop,
+        ui_state.beats_per_loop,
+    );
     draw_note_successes(
         &current_loop_hits,
         &ui_state.desired_hits,
@@ -686,14 +647,14 @@ fn draw_beat_grid(ui_state: &UIState, ui: &mut egui::Ui, events: &mut Vec<Events
             Instrument::Tom3 => "Tom3 (Low)",
             Instrument::PedalHiHat => "Pedal Hi-hat",
         };
-        let t_rect = rect_for_col_row(0, row, to_screen, width_scale, height_scale);
+        let t_rect = rect_for_col_row(0., row, to_screen, width_scale, height_scale);
         let label = egui::Label::new(name);
         ui.put(t_rect, label);
     }
 }
 
 fn rect_for_col_row(
-    col: usize,
+    col: f64,
     row: usize,
     to_screen: RectTransform,
     width_scale: f32,
@@ -739,7 +700,11 @@ fn draw_user_hits(
     visible_instruments: &[&Instrument],
 ) {
     for (instrument_idx, instrument) in visible_instruments.iter().enumerate() {
-        let user_notes = get_user_hit_timings_by_instrument(&ui_state.user_hits, **instrument);
+        let user_notes = get_user_hit_timings_by_instrument(
+            &ui_state.user_hits,
+            **instrument,
+            ui_state.beats_per_loop,
+        );
         let desired_notes = ui_state.desired_hits.get_instrument_beats(instrument);
         for note in user_notes.iter() {
             draw_user_hit(
@@ -820,7 +785,7 @@ fn draw_note_successes(
     beats_per_loop: usize,
 ) {
     for (instrument_idx, instrument) in visible_instruments.iter().enumerate() {
-        let actual = get_user_hit_timings_by_instrument(user_hits, **instrument);
+        let actual = get_user_hit_timings_by_instrument(user_hits, **instrument, beats_per_loop);
         // add audio_latency to each note
         let actual_w_latency = actual
             .iter()
@@ -857,8 +822,7 @@ fn note_success_shape(
     width_scale: f32,
     height_scale: f32,
 ) -> Shape {
-    let col = beats_offset as usize; // TODO: truncate, for now
-    let rect = rect_for_col_row(col, row, to_screen, width_scale, height_scale);
+    let rect = rect_for_col_row(beats_offset, row, to_screen, width_scale, height_scale);
 
     let bar_color = match acc {
         Accuracy::Early => ORANGE,
@@ -887,6 +851,7 @@ fn gold_mode(ui: &mut egui::Ui, ui_state: &UIState) {
         let nth_loop_hits = get_hits_from_nth_loop(
             &ui_state.user_hits,
             (ui_state.current_loop as i32 - i) as usize, // TODO: check for overflow
+            ui_state.beats_per_loop,
         );
         let summary_data = compute_last_loop_summary(
             &nth_loop_hits,
diff --git a/src/game.rs b/src/game.rs
index 27d620f..ddf85ef 100644
--- a/src/game.rs
+++ b/src/game.rs
@@ -109,7 +109,6 @@ pub fn compute_ui_state(gs: &GameState, audio: &Audio, midi_device_name: &str) -
     ui_state.set_selected_idx(gs.selected_loop_idx);
     ui_state.set_current_beat(audio.current_beat());
     ui_state.set_current_loop(audio.current_loop() as usize);
-    ui_state.set_enabled_beats(&gs.voices, gs.beats_per_loop);
     ui_state.set_is_playing(!audio.is_paused());
     ui_state.set_bpm(audio.get_bpm() as f32);
     ui_state.set_audio_latency_s(audio.get_configured_audio_latency_seconds() as f32);
@@ -148,8 +147,11 @@ pub fn process_system_events(
         match msg {
             TxMsg::AudioNew => (),
             TxMsg::StartingLoop(loop_num) => {
-                let last_loop_hits =
-                    get_hits_from_nth_loop(&audio.user_hits, (audio.current_loop() - 1) as usize);
+                let last_loop_hits = get_hits_from_nth_loop(
+                    &audio.user_hits,
+                    (audio.current_loop() - 1) as usize,
+                    beats_per_loop,
+                );
                 let summary_data =
                     compute_last_loop_summary(&last_loop_hits, voices, beats_per_loop);
                 info!("last loop summary = {:?}", summary_data);
diff --git a/src/score.rs b/src/score.rs
index 573d50d..3cb17f0 100644
--- a/src/score.rs
+++ b/src/score.rs
@@ -6,7 +6,7 @@ use std::{collections::HashMap, vec};
 
 use crate::{
     consts::UserHit,
-    consts::{ALL_INSTRUMENTS, BEATS_PER_LOOP},
+    consts::ALL_INSTRUMENTS,
     voices::{Instrument, Voices},
 };
 
@@ -176,11 +176,12 @@ impl LastLoopSummary {
 pub fn get_user_hit_timings_by_instrument(
     user_hits: &[UserHit],
     instrument: Instrument,
+    beats_per_loop: usize,
 ) -> Vec<f64> {
     user_hits
         .iter()
         .filter(|hit| hit.instrument == instrument)
-        .map(|hit| hit.beat(BEATS_PER_LOOP))
+        .map(|hit| hit.beat(beats_per_loop))
         .collect::<Vec<f64>>()
 }
 
@@ -231,7 +232,8 @@ pub fn compute_last_loop_summary(
 
     for instrument in ALL_INSTRUMENTS.iter() {
         // get accuracy of hihat
-        let user_timings = get_user_hit_timings_by_instrument(user_hits, *instrument);
+        let user_timings =
+            get_user_hit_timings_by_instrument(user_hits, *instrument, beats_per_loop);
         let desired_timings = desired_hits.get_instrument_beats(instrument);
 
         let accuracies = compute_loop_performance_for_voice(
@@ -247,12 +249,17 @@ pub fn compute_last_loop_summary(
     out
 }
 
-pub fn get_hits_from_nth_loop(user_hits: &[UserHit], desired_loop_idx: usize) -> Vec<UserHit> {
+pub fn get_hits_from_nth_loop(
+    user_hits: &[UserHit],
+    desired_loop_idx: usize,
+    beats_per_loop: usize,
+) -> Vec<UserHit> {
     let last_loop_hits: Vec<UserHit> = user_hits
         .iter()
         .filter(|hit| {
             // include hits from just before start of loop (back to 0 - MISS), since those could be early or on-time hits
-            let loop_num_for_hit = ((hit.clock_tick + MISS_MARGIN) / BEATS_PER_LOOP) as usize;
+            let loop_num_for_hit =
+                ((hit.clock_tick + MISS_MARGIN) / beats_per_loop as f64) as usize;
             loop_num_for_hit == desired_loop_idx
         })
         .cloned()
diff --git a/src/voices.rs b/src/voices.rs
index 543d38c..8a122f7 100644
--- a/src/voices.rs
+++ b/src/voices.rs
@@ -5,7 +5,7 @@ use std::error::Error;
 
 use serde::{Deserialize, Serialize};
 
-use crate::consts::{ALL_INSTRUMENTS, GRID_COLS, GRID_ROWS};
+use crate::consts::ALL_INSTRUMENTS;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum Instrument {
@@ -147,24 +147,6 @@ impl Voices {
             // Instrument::Metronome => "assets/sounds/click.wav",
         }
     }
-
-    // TODO: how to handle a dynamic number of cols.. vec?
-    // TODO: Probably better to represent this without arrays
-    pub fn to_enabled_beats(&self, beats_per_loop: usize) -> [[bool; GRID_COLS]; GRID_ROWS] {
-        let mut out = [[false; GRID_COLS]; GRID_ROWS];
-
-        for (instrument_idx, instrument) in ALL_INSTRUMENTS.iter().enumerate() {
-            for beat in self.get_instrument_beats(instrument) {
-                for val in 0..beats_per_loop {
-                    if *beat == (val as f64) {
-                        out[instrument_idx][val] = true;
-                    }
-                }
-            }
-        }
-
-        out
-    }
 }
 
 /// Loop is the full information required to play a loop. It can be read/written to a file.