Warning: this is an htmlized version!
The original is across this link,
and the conversion rules are here.
Lua 5.1.5  Copyright (C) 1994-2012 Lua.org, PUC-Rio
> dofile "newrect.lua"
> lp = LPicture.new {cellfont="\\scriptsize"}
> for l=0,2 do
>>   for r=0,3 do
>>     local pos=lr(l, r)
>>     lp:put(pos, pos:xy())
>>   end
>> end
> = lp
\vcenter{\hbox{\unitlength=10pt%
\celllower=2.5pt%
\def\cellfont{\scriptsize}%
\begin{picture}(6,6)(-2.5,-0.5)
  \put(0,0){\cell{(0,0)}}
  \put(1,1){\cell{(1,1)}}
  \put(2,2){\cell{(2,2)}}
  \put(3,3){\cell{(3,3)}}
  \put(-1,1){\cell{(-1,1)}}
  \put(0,2){\cell{(0,2)}}
  \put(1,3){\cell{(1,3)}}
  \put(2,4){\cell{(2,4)}}
  \put(-2,2){\cell{(-2,2)}}
  \put(-1,3){\cell{(-1,3)}}
  \put(0,4){\cell{(0,4)}}
  \put(1,5){\cell{(1,5)}}
\end{picture}}}
> 
>