\nopdfcompression

\definecolor         [xcyan]   [c=1]
\definecolor         [xmagenta][m=1]
\definecolor         [xyellow] [y=1]

\definespotcolor     [scyan]   [xcyan]   [p=1]
\definespotcolor     [smagenta][xmagenta][p=1]
\definespotcolor     [syellow] [xyellow] [p=1]

\definemultitonecolor[scombi]  [xcyan=.2,xmagenta=.4,xyellow=.6][c=.2,m=.4,y=.6]

\startTEXpage
    \hbox \bgroup
        \blackrule[color=scyan,   width=1cm,height=1cm,depth=0cm]%
        \blackrule[color=smagenta,width=1cm,height=1cm,depth=0cm]%
        \blackrule[color=syellow, width=1cm,height=1cm,depth=0cm]%
        \blackrule[color=scombi,  width=1cm,height=1cm,depth=0cm]%
    \egroup
\stopTEXpage
