diff --git a/app-proto/src/display.rs b/app-proto/src/display.rs
index 2e9b4f0..59d0dca 100644
--- a/app-proto/src/display.rs
+++ b/app-proto/src/display.rs
@@ -408,6 +408,8 @@ pub fn Display() -> View {
             }
             
             if scene_changed.get() {
+                const SPACE_DIM: usize = 3;
+                
                 /* INSTRUMENTS */
                 // measure mean frame interval
                 frames_since_last_sample += 1;
@@ -486,7 +488,6 @@ pub fn Display() -> View {
                         point(0.0, -0.15, -1.0)
                     ];
                     
-                    const SPACE_DIM: usize = 3;
                     let asm_to_world_sp = asm_to_world.rows(0, SPACE_DIM);
                     let point_reps_world_sp = point_reps.map(|rep| &asm_to_world_sp * rep);
                     DMatrix::from_columns(&point_reps_world_sp).cast::<f32>()
@@ -532,7 +533,7 @@ pub fn Display() -> View {
                 
                 // bind the viewport vertex position buffer to the position
                 // attribute in the vertex shader
-                bind_to_attribute(&ctx, viewport_position_attr, 3, &viewport_position_buffer);
+                bind_to_attribute(&ctx, viewport_position_attr, SPACE_DIM as i32, &viewport_position_buffer);
                 
                 // draw the scene
                 ctx.draw_arrays(WebGl2RenderingContext::TRIANGLES, 0, VERTEX_CNT as i32);
@@ -545,7 +546,7 @@ pub fn Display() -> View {
                 // load the point positions into a new buffer and bind it to the
                 // position attribute in the vertex shader
                 let point_position_buffer = load_new_buffer(&ctx, point_positions.as_slice());
-                bind_to_attribute(&ctx, point_position_attr, 3, &point_position_buffer);
+                bind_to_attribute(&ctx, point_position_attr, SPACE_DIM as i32, &point_position_buffer);
                 
                 // draw the scene
                 ctx.draw_arrays(WebGl2RenderingContext::POINTS, 0, point_positions.ncols() as i32);