Question: I am attempting to typeset a notation that I use for my own work, and I am struggling to create flexible commands. The notation involves placing mathematical symbols and expressions as if on the vertices of a triangular grid, and then using these objects in equations, resulting in images like these:

![notation](https://i.stack.imgur.com/LZUnj.png)

![notation1](https://i.stack.imgur.com/sXrxz.png)

![notation2](https://i.stack.imgur.com/G2av5.png)

![notation3](https://i.stack.imgur.com/WeAAK.png)

Until now I have been fiddling with `tikzpicture` and painstakingly adjusting node positions until it looks right, but I want to create some commands or a package that would allow me to select the structure, like `twoOverThree` in the fourth image, and input the arguments `{a}{b}{c}{d}{e}` whether they are single letters or slightly more complicated expressions. Any advice? The `tikzpicture` strategy failed to work generally because adjustments in node positioning were always necessary depending on the arguments.

Answer: 
All this notation can be replicated with simple `arrays`, why do you need `TikZ`?

```
\documentclass{article}
\usepackage{amsmath,array}

\newcommand{\twooverthree}[5]{
    \begin{array}{@{}c@{}c@{}c@{}c@{}c@{}}
        &#1&&#2\\
        #3&&#4&&#5
    \end{array}}

\newcommand{\twooverone}[3]{
    \begin{array}{@{}c@{}c@{}c@{}}
        #1&&#2\\
        &#3
    \end{array}}

\newcommand{\oneovertwo}[3]{
    \begin{array}{@{}c@{}c@{}c@{}}
        &#1\\
        #2&&#3\\
    \end{array}}

\newcommand{\oneone}[2]{
    \begin{array}{@{}c@{}c@{}}
        #1\\
        &#2\\
    \end{array}}

\begin{document}
\[
\left(\oneone{a}{b}\right)\left(\oneone{d}{e}\right)
\]

\[
\alpha\left(\twooverone{a}{c}{b}\right) = 
\oneovertwo{\alpha b}{\alpha c}{\alpha a}
\]

\[
\oneone{\oneone{a}{\overline{v}}}{\oneone{\overline{w}}{f}}
\]

\[
\twooverthree{a}{b}{c}{d}{e}
\]
\end{document}

```

![enter image description here](https://i.stack.imgur.com/KLLN0.png)
These are trivial to set up with `stackengine` macros (original answer) and even easier still with the `tabstackengine` package (revised answer). However, I don't feel I have enough info to set up macro shortcuts, since I don't know the full extent of the desired syntax.

Since many of your data items were in upright (non-math) font, I made the default settings to be that way. If the items in your notation are generally math items, just issue `\stackMath` in the preamble, and the stacks will assume the arguments are math mode.

**REVISED ANSWER**

```
\documentclass{article}
\usepackage{tabstackengine}
\def\stacktype{L}\setstackgap{L}{.8\baselineskip}
\begin{document}
\[ 
\Bigl( \tabbedstackanchor{a&}{&b}\Bigr)
\Bigl( \tabbedCenterstack{d&\\&e}\Bigr)
\]

\[
\alpha\Bigl( \tabbedstackanchor{a&&c}{&b&} \Bigr) = 
  \tabbedstackanchor{&$\alpha$b&}{$\alpha$c&&$\alpha$a}
\]

\[
\tabbedCenterstack{a&&&\\&$\bar v$&&\\&&$\bar w$&\\&&&f} = 0
\]

\[
\tabbedstackanchor{&b&&d&}{a&&c&&e}
\]
\end{document}

```

![enter image description here](https://i.stack.imgur.com/WNuT0.jpg)

**ORIGINAL ANSWER** (`stackengine`)

In the MWE below, I show various ways to get the results.

```
\documentclass{article}
\usepackage[usestackEOL]{stackengine}
\def\stacktype{L}\setstackgap{L}{.8\baselineskip}
\begin{document}
\[ 
\Bigl( \stackanchor{a~~}{~~b}\Bigr)
\Bigl( \Centerstack{d~~\\~~e}\Bigr)
\]

\[
\alpha\Bigl( \stackanchor{a~~c}{b} \Bigr) = 
  \stackanchor{$\alpha$b}{$\alpha$c~~~$\alpha$a}
\]

\[
\makebox[7ex]{%
\tllap[.5\dimexpr\Lstackgap\relax]{\tllap{a}$\bar v$}\brlap[.5\dimexpr\Lstackgap\relax]{$\bar w$\brlap{f}}
}  = 0
\]

\[
\stackanchor{b~~d}{a~~c~~e}
\]
\end{document}

```

![enter image description here](https://i.stack.imgur.com/kuZ4m.jpg)