Okay, here's my current leading evolved bot from the sim described above.
else
1 1 15 store
12 0 0 -3 1 -32 start
add 23 *.robage 24 57 mult sub add .repro store
cond
start
0 and
1 -10 -24 angle 13 .up store
stop
9 1 1 -16 start
start
<
0 1 not
.shoot dec
rnd dist -7 -6 1 2 0 start
stop
-2 -1 - 8 0 1 1 *20 1 9 2 -16 0 stop
start
20 0 angle 8 13 0 1 11 & 23 -23 1 add cond
stop
else
1 1 1 *.up 0 -1 and
*.up 0 1 1 %=
else
start
16 add -1 0 30 start
1 -13 0 0 1 0 1 *-9 start
1 1 11 19 1 7 add and
store
.up inc
0 8 -1 *-18 start
1 0 angle 1 15 5 start
angle *-4 and
~ 0 *.up inc
sqr
Strangely, the repro command was placed in the middle of the dna, so either the reproduction commands migrated to the top of the dna somehow or a mutation wiped out the original repro instruction and later on created a new one higher up the dna in a sterile bot.
This bot reproduces every 1300 or so cycles, and it is being plunged into sims with slowly-increasing costs to try and temper it a little.
I think it overflows the value in .repro based on its age until it happens to hit a >0 value.