diff --git a/main.cxx b/main.cxx
index b4e726c..792cb9d 100644
--- a/main.cxx
+++ b/main.cxx
@@ -90,10 +90,10 @@ struct sparse_entry_t {
 } g_a[Y][X];
 
 // marker particle data
-const size_t N = 4*Y*X;
+const size_t k_max_marker_count = 4*Y*X;
 size_t g_markers_length;
 bool g_source_exhausted;
-vec2f g_markers[N];
+vec2f g_markers[k_max_marker_count];
 uint8_t g_marker_count[Y][X];
 uint8_t g_old_marker_count[Y][X];
 
@@ -301,7 +301,6 @@ void sim_init(args_t in) {
   if (g_rainbow_enabled) {
     colorize();
   }
-
 }
 
 void update_fluid_sources() {
@@ -309,7 +308,7 @@ void update_fluid_sources() {
   // The current extrapolation implementation assumes that the fluid is never
   // more than one cell from a cell where fluid was in the previous step. If
   // we stop and then later restart generating fluid, that may not hold true.
-  g_source_exhausted |= (g_markers_length == N-1);
+  g_source_exhausted |= (g_markers_length == k_max_marker_count-1);
 
   float t = 0.6f / k_source_color_period * g_frame_count;
   for (size_t y = 0; y < Y; ++y) {
@@ -318,7 +317,7 @@ void update_fluid_sources() {
         if (!g_source_exhausted && g_marker_count[y][x] < 4) {
           g_markers[g_markers_length++] = k_s*vec2f{x+g_rng(), y+g_rng()};
           g_marker_count[y][x]++;
-          g_source_exhausted |= (g_markers_length == N-1);
+          g_source_exhausted |= (g_markers_length == k_max_marker_count-1);
         }
         g_r[y][x] = hsv_basis(t + 2.f);
         g_g[y][x] = hsv_basis(t);