! mnapply behaves mysteriously for n >= 4.

USE: generalizations
IN: scratchpad 1 1 [ * . ] 2 1 mnapply
1
IN: scratchpad 1 1 2 2 [ * . ] 2 2 mnapply
1
4
IN: scratchpad 1 1 2 2 3 3 [ * . ] 2 3 mnapply
1
4
9
IN: scratchpad 1 1 2 2 3 3 4 4 [ * . ] 2 4 mnapply
! Error: stack underflow
IN: scratchpad [ 1 1 2 2 3 3 4 4 [ * . ] 2 4 mnapply ] infer.
( x x -- x x )
IN: scratchpad [ 1 1 2 2 3 3 [ * . ] 2 3 mnapply ] infer.
( -- )
IN: scratchpad [ 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 [ * . ] 2 9 mnapply ] infer.
( x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x -- x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x )