H Depthwise

H1

BL - edge FL

L'U'L2UL'

BR - edge FR

RUR2'U'R

FL - edge BR

LUL2'U'L

FR - edge BR

R'U'R2UR'

H2

BL - edge FL

L2'ULU'L'UL'

LUL2'U'L2UL'

reduction by LUL'

BR - edge FR

R2U'R'URU'R

from JUN

R'U'R2UR2'U'R

reduction by R'U'R

FL - edge BL

L2U'L'ULU'L

L'U'L2UL2'U'L

reduction by L'U'L

FR - edge BR

R2'URU'R'UR'

RUR2'U'R2UR'

reduction by RUR'; from Lars Vandenbergh