Abstract Rewriting Challenge (Cops)
326 points - Cracked by jimmy23013
The level is Picokosmos #13 by Aymeric du Peloux (with a trivial modification). I tried to find a tasteful level that could be implemented with &quot;boxes&quot; and &quot;walls&quot; being the same character. For this level it was possible by making the central choke point two columns wide rather than one.
The rules/initial/target strings could be golfed a bit more, but this is just for fun.
Initial string:
___##___####_____##_#_#_##_#_!####______##_#####__####_#_######__###__

Target string:
___##___####_____##_#_#_##_#_#####____!__#_#####__####_#_######__###__

Rules:
_wW:!
_&lt;:&lt;_
Vv_:!
V_:_V
R:&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;
V#:#V
#w&lt;:w#
&gt;v_:_v
_wX:#
_!:!_
!:wLW_
L:&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;
#W:W#
!#_:_!#
_w&lt;:w_
#&lt;:&lt;#
!:_VRv
&gt;v#:#v
Uv_:#
_W:W_
_X:X_
&gt;#:#&gt;
#X:X#
U_:_U
Vv#:!URv
#wW:wLX!
&gt;_:_&gt;
!_:_!
_#!:#!_
U#:#U