http://qs321.pair.com?node_id=301203

UPDATE: I've done it!!!! 4 lines:
```@m=((31,(15)x8)x8,(31)x9);\$m[\$c]|=16,!(@a=grep/-?./&!(16+\$|*\$'&\$m[\$c+\$
+&]
),-18,11,94,-92)?\$c=pop@p:\${\$_=\$a[rand@a];s/-?.//;push@p,\$c;\$m[\$c]&=~(
+8/
\$_);++\$u-64?\$m[\$c+=\$&]&=~\$_:map\$_&=15,@m,\$c=\$|=1},\$|&&9x3e7,print"\ec"
+,
map\$_%9?(\$_-\$c?\$m[\$_]&2?_:\$":o).(\$m[\$_]&8?"|":_):\$/,1..72until\$c>70&\$|
It uses a horrible horrible hack for the select (9x3e7 which takes ~10 ms on my machine, but YMMV, if it works at all... (you can increase the e7 to slow down, lower it to speed up)

also still needs vt100 (for \ec). and yes, had to make some allowances to get it into 4 lines... ho hum.
al

the original post is in the readmore:

so i've been trying to compress these obfus for ages into a single 4 line sig. unfortunately i can only just get it shorter than 5 lines.

so here's the best i can do (including suggestions from people here), as ever it requires VT100.

```@m=((31,(15)x15)x10,(31)x16);\$m[\$c]|=16,!(@a=grep!(\$m[\$c+\$\$_[0]]&16+\$s
+*\$
\$_[1]),[-1,8],[1,1],[16,4],[-16,2])?\$c=pop@p:\${(\$i,\$j)=@{\$a[rand@a]};\$
+m[
\$c]&=~8/\$j;push@p,\$c;\$m[\$c+=\$i]&=~\$j;++\$u-150||map\$_&=15,@m,\$c=\$s=1},
+\$s
&&select\$x,\$x,\$x,.1*print"\ec",(_)x31,map\$_%16?(\$_-\$c?\$m[\$_]&2?_:\$":o)
+.(
\$m[\$_]&8?"|":_):"\$/|",0..160until\$c>158&\$s
if anyone can golf it down to 4 lines (of 72 chars - i need to lose 42 chars) i'd be
• surprised :-)

• eternally grateful

it's all explained here:
SPOILER:
it basically does 2 passes using depth first search:
```#set up maze - only border visited
@m=((31,(15)x15)x10,(31)x16);
# until loop starts now

#say we've visited current square
\$m[\$c]|=16,

#find possibilities (on 1st pass (\$s=0) just check visited
# on second pass also check the bit is unset for that direction
# 4
#8 1
# 2
!(@a=grep
!(\$m[\$c+\$\$_[0]]&16+\$s*\$\$_[1]),
[-1,8],[1,1],[16,4],[-16,2]

)?
# if one isn't found then go back
\$c=pop@p:
# if one is found, then pick it and unset the bits (ie allow access th
+rough)
\${
(\$i,\$j)=@{\$a[rand@a]};
\$m[\$c]&=~8/\$j;
push@p,\$c;
\$m[\$c+=\$i]&=~\$j;

# and finish if we visit them all (unset visited bit in @m)
++\$u-150||map\$_&=15,@m,\$c=\$s=1
}

# and draw  (space is here for formatting in wrapped version)
\$s&&
select\$x,\$x,\$x,.1*print"\ec",
(_)x31,
map\$_%16?(\$_-\$c?\$m[\$_]&2?_:\$":o).(\$m[\$_]&8?"|":_):"\$/|",0..160
# and redo unless it's the end
until\$c>158&\$s