Optical illusions, 3/5
\documentclass[tikz,border=10pt]{standalone} %% definition of the central band, just to show %% that in both configurations the same color is used \newcommand{\colorband}[1][]{% \foreach \a in {0.2,0.6,...,4} \draw[line width=0.2cm,#1] (\a,1)--(\a,2);} %% definition of the remaining part \newcommand{\stripes}[1][]{% \foreach \b in {0,0.4,...,4} \draw[line width=0.2cm,#1] (\b,0)--(\b,3);} \newcommand{\middlestripes}[1][]{% \foreach \b in {0.2,0.6,...,4} \draw[line width=0.2cm,#1] (\b,0)--(\b,1)(\b,2)--(\b,3);} \begin{document} \begin{tikzpicture} %% red band, orange and magenta perception \colorband[red] \stripes[yellow] \middlestripes[blue] \begin{scope}[xshift=6cm] \colorband[red] \stripes[blue] \middlestripes[yellow] \end{scope} \begin{scope}[yshift=4cm] %% green band, lime and cyan perception \colorband[green] \stripes[yellow] \middlestripes[blue] \begin{scope}[xshift=6cm] \colorband[green] \stripes[blue] \middlestripes[yellow] \end{scope} \end{scope} \end{tikzpicture} \end{document}