$($a$)$

$11$

$1$

$11$

$11$

$111$

$111$

$11111$

$($b$)111$

$($c$)1111$

$($d$)11I$

$11111$

IIII

IIII

IIIIIII

$111111$

IIIII

$4.$ Suppose that only one or two or five sticks can be removed from each pile. Repeat the games in Exercise $1$ with this constraint.

a$,$b only