diff --git a/evolve.go b/evolve.go
new file mode 100644
index 0000000..565aad8
--- /dev/null
+++ b/evolve.go
@@ -0,0 +1,189 @@
+package main
+
+import (
+	"fmt"
+	"math/rand"
+	"strconv"
+	"time"
+	"strings"
+	"io/ioutil"
+)
+
+type sensor struct {
+	srange int
+	angle int
+	width int
+	turret bool
+}
+
+type Tank struct {
+	color string
+	sensors [10]sensor
+	program []string
+}
+
+var symbols []string = []string{
+	"~",
+  "!",
+  "+",
+  "-",
+  "*",
+  "/",
+  "%",
+  "&",
+  "|",
+  "^",
+  "<<",
+  ">>",
+  ">",
+  ">=",
+  "<",
+  "<=",
+  "=",
+  "<>",
+  "abs",
+  "dup",
+  "pop",
+  "exch",
+  "if",
+  "ifelse",
+  "mset",
+  "mget",
+  "{",
+  "}",
+  "fire-ready?",
+  "fire!",
+  "set-speed!",
+  "get-turret",
+  "set-turret!",
+  "sensor?",
+  "set-led!",
+  "random",
+}
+
+func make_nucleotide() int {
+	switch rand.Intn(3) {
+	case 0:
+	  return rand.Intn(len(symbols))
+	case 1:
+	  return len(symbols) + rand.Intn(720)
+	 case 2:
+		return len(symbols) + 720 + rand.Intn(100)
+	}
+	return 0
+}
+
+func make_dna(size int) []int {
+	ret := make([]int, size)
+	for i := 0; i < size; i += 1 {
+		ret[i] = make_nucleotide()
+	}
+	return ret
+}
+
+func color_of_dna(dna []int) (string, []int) {
+	if len(dna) >= 3 {
+		r := dna[0] % 256
+		g := dna[1] % 256
+		b := dna[2] % 256
+		color := fmt.Sprintf("%02x%02x%02x", r, g, b)
+		return color, dna[3:]
+	} else {
+		return "cccccc", dna
+	}
+}
+
+func sensor_of_dna(dna []int) (sensor, []int) {
+	if len(dna) >= 4 {
+		return sensor{dna[0], dna[1], dna[2], dna[3] % 2 == 0}, dna[4:]
+	} else {
+		return sensor{0, 0, 0, false}, dna
+	}
+}
+
+func program_of_dna(dna []int) []string {
+	ret := make([]string, 0, len(dna))
+	
+	stacks := []int{}
+	for i := 0; i < len(dna); i += 1 {
+		// If we are in a stack, decrement the size
+		if len(stacks) > 0 {
+			stacks[0] -= 1
+			// Are we at the end of the stack? Output the symbol and pop the stack off.
+			if stacks[0] <= 0 {
+				ret = append(ret, "}")
+				stacks = stacks[1:]
+			}
+		}
+		
+		// Consider the next nucleotide
+		n := dna[i]
+
+		// Symbol?
+		if n < len(symbols) {
+			ret = append(ret, symbols[n])
+			continue
+		}
+		n -= len(symbols)
+		
+		// Number?
+		if n < 720 {
+			ret = append(ret, strconv.Itoa(n - 360))
+			continue
+		}
+		n -= 720
+		
+		// Stack.
+		ret = append(ret, "{")
+		stacks = append(stacks, (n + 1) % (len(dna) - i))
+	}
+	
+	for len(stacks) > 0 {
+		ret = append(ret, "}")
+		stacks = stacks[1:]
+	}
+	
+	return ret
+}
+
+func tank_of_dna(dna []int) Tank {
+	ret := Tank{}
+	ret.color, dna = color_of_dna(dna)
+	for i := 0; i < len(ret.sensors); i += 1 {
+		ret.sensors[i], dna = sensor_of_dna(dna)
+	}
+	ret.program = program_of_dna(dna)
+	
+	return ret
+}
+
+func twrite(num int, fn string, contents string) {
+	path := fmt.Sprintf("tank.%d/%s", num, fn)
+	ioutil.WriteFile(path, []byte(contents), 0644)
+}
+
+func (t Tank) Write(num int, dir string) {
+	twrite(num, "color", t.color)
+	for i := 0; i < len(t.sensors); i += 1 {
+		turret := 0
+		if t.sensors[i].turret {
+			turret = 1
+		}
+		twrite(
+			num,
+			fmt.Sprintf("sensor%d", i),
+			fmt.Sprintf("%d %d %d %d", t.sensors[i].srange, t.sensors[i].angle, t.sensors[i].width, turret),
+		)
+	}
+	twrite(num, "program", strings.Join(t.program, " "))
+}
+
+func init() {
+	rand.Seed(time.Now().UTC().UnixNano())
+}
+
+func main() {
+	d := make_dna(20)
+	p := program_of_dna(d)
+	fmt.Println(p)
+}
\ No newline at end of file