diff --git a/src/modules/automata.js b/src/modules/automata.js
index 4fb914c..e8ee506 100644
--- a/src/modules/automata.js
+++ b/src/modules/automata.js
@@ -20,14 +20,31 @@ function evolve1d(state, rules) {
 }
 
 // create a 2D board from a 1D CA initial state
+// function createBoard(state, rules, height) {
+//   function createBoardAcc(s, h, acc) {
+//     if (h === 0) return acc;
+//     const newState = evolve1d(s, rules);
+//     const newAcc = acc.concat([s]);
+//     return createBoardAcc(newState, h - 1, newAcc);
+//   }
+//   return createBoardAcc(state, height, []);
+// }
+
+// performance "choke point" in full imperative
 function createBoard(state, rules, height) {
-  function createBoardAcc(s, h, acc) {
-    if (h === 0) return acc;
-    const newState = evolve1d(s, rules);
-    const newAcc = acc.concat([s]);
-    return createBoardAcc(newState, h - 1, newAcc);
+  var board = [];
+  let prevState = [];
+  for (let i = 0; i < height; i++) {
+    let nextState = [];
+    if (i == 0) {
+      nextState = evolve1d(state, rules);
+    } else {
+      nextState = evolve1d(prevState, rules);
+    }
+    board = board.concat([nextState]);
+    prevState = nextState;
   }
-  return createBoardAcc(state, height, []);
+  return board;
 }
 
 // Find the neighbor of a given cell in a 2D CA board