# Make a 2cell diagram more beautiful (or less ugly)

I want to draw a two-cell diagram using xypic, the problem is that the bigone label is to long, how can I make the following diagram:

looks like this one:

using exclusively the two-cell feature of xypic, or at least, keep the \uppertwocell and \lowertwocell commands and draw a {=>} arrow using -| feature.

Here is the code:

\xymatrix{\star &  & \star\lltwocell_{g{}_{1}g{}_{2}}^{g''_{1}g''_{2}}<7>{^{(\alpha'\circ\beta')\bullet(\alpha\circ\beta)}}}


Knowing that the second diagram was drawn using \ar commands, but in LyX environment, which prevent from scrolling horizontally the window, using only \ar commands is not very comfortable!

• Just so you know: horizontal scrolling is coming. Not in LyX 2.1, but probably 2.2. – scottkosty Oct 4 '13 at 19:58
• Very good news! I hope it will not be after I finished my thesis :-D – ubugnu Oct 4 '13 at 20:08

One approach with tikz-cd:

\documentclass{standalone}
\usepackage{tikz-cd}

\begin{document}
\begin{tikzcd}
\star
\arrow[from=rr,bend right,"g_1 g_2"{above,name=U}]
\arrow[from=rr,bend left,"g_1'' g_2''"{below,name=D}] &
(\alpha' \circ \beta') \bullet (\alpha \circ \beta)
\arrow[equal,from=U,shorten <=0.3333em] % 0.3333em from default inner sep value
\arrow[Rightarrow,to=D,shorten >=0.3333em] &
\star
\end{tikzcd}
\end{document}