diff --git a/examples/coremem.rs b/examples/coremem.rs
index 668760c..1677ba1 100644
--- a/examples/coremem.rs
+++ b/examples/coremem.rs
@@ -8,7 +8,10 @@ fn main() {
     let mut step = 0u64;
     loop {
         step += 1;
-        state.impulse_ey(50, 50, 50f32 * ((step as f64)*0.1f64).sin() as f32);
+        let imp = 50.0 * ((step as f64)*0.05).sin() as f32;
+        state.impulse_ex(50, 50, imp);
+        state.impulse_ey(50, 50, imp);
+        //state.impulse_bz(50, 50, imp / 3e8f32);
         Renderer.render(&state);
         state.step();
         thread::sleep(time::Duration::from_millis(33));
diff --git a/src/render.rs b/src/render.rs
index 6d9534b..5030223 100644
--- a/src/render.rs
+++ b/src/render.rs
@@ -33,6 +33,15 @@ fn norm_color(v: f32) -> u8 {
     (v * 64.0 + 128.0).max(0f32).min(255f32) as u8
 }
 
+fn curl(x: f32, y: f32) -> f32 {
+    let c = x * y;
+    if c >= 0f32 {
+        c.sqrt()
+    } else {
+        -(-c).sqrt()
+    }
+}
+
 impl ColorTermRenderer {
     pub fn render(&self, state: &SimState) {
         let mut buf = String::new();
@@ -42,8 +51,11 @@ impl ColorTermRenderer {
                 let cell = state.get(x, y);
                 //let r = norm_color(cell.bz() * consts::C);
                 let r = 0;
-                let g = norm_color(cell.ex());
-                let b = norm_color(cell.ey());
+                let b = 0;
+                //let g = norm_color(cell.ex());
+                //let b = norm_color(cell.ey());
+                //let g = norm_color(curl(cell.ex(), cell.ey()));
+                let g = norm_color(cell.bz() * 3.0e8);
                 write!(&mut buf, "{}", RGB(r, g, b).paint(square));
             }
             write!(&mut buf, "\n");