User blog comment:Wythagoras/FGH of Dollar Function new version/@comment-11227630-20131022073239/@comment-10429372-20131022074146

&-> expands to a&a&a...a&a&a, beacause -> expands to a,a,a...a,a,a. I need to make rules for &k. They work like normal &'s, but works in the arrows of &k-1.