Constraints
-----------

* I want to use the same name for inner and outer loop.
* I am reluctant to append `@` and make use of `\makeatletter...\makeatother`.

Is there any name-spacing construct to use?

MWE
---

The following code will not produce the correct result as the two `\i` clash.

```
\documentclass[pstricks,border=12pt]{standalone}
\usepackage{multido}
\SpecialCoor
\def\Triangle(#1)#2{{\rput(#1){\multido{\i=0+1}{#2}{\multips(\i,0)(!.5 3 sqrt 2 div){\numexpr#2-\i\relax}{\pspolygon(1,0)(!.5 3 sqrt 2 div)}}}}}

\usepackage[nomessages]{fp}
\FPset\N{4}
\FPeval\Width{(N-1)*(N+2)/2+N}
\FPeval\Height{round(root(2,3)*N/2:6)}

\begin{document}
\begin{pspicture}(\Width,\Height)
    \multido{\i=1+1}{\N}{\Triangle(!\i\space 1 sub \i\space 2 add mul 2 div 0){\i}}
\end{pspicture}
\end{document}

```

The correct output is as follows.

![enter image description here](https://i.stack.imgur.com/3DGpY.png)