$!
D x (y. x (z. y z))
C x (y. x (z. y y))

$!
D x (y1. x (y2. x (y3. y1 y2 y3)))
C x (y1. x (y2. x (y3. y1 y1 y3)))
C x (y1. x (y2. x (y3. y1 y3 y3)))
C x (y1. x (y2. x (y3. y1 y2 y1)))
C x (y1. x (y2. x (y3. y1 y2 y2)))

$!
D x (y1. x (y2. x (y3. x (y4. y1 y2 y3 y4))))
C x (y1. x (y2. x (y3. x (y4. y1 y2 y3 y1))))
C x (y1. x (y2. x (y3. x (y4. y1 y2 y1 y4))))