Conway o ** *x xx
Crystal. p1 pm cm pg
Conway 2222 *2222 2*22 22* 22x
Crystal. p2 pmm cmm pmg pgg
Conway 333 *333 3*3
Crystal. p3 p3m1 p31m
Conway 442 *442 4*2
Crystal. p4 p4m p4g
Conway 632 *632
Crystal. p6 p6m
Least
rotation
angle
Orientation preserving
(No reflections or glides)
Mirrors meet all glide axes
and centers of rotation
Has independent glides
or centers of rotation

p1 (o)

pm (**)
Has refections?
Yes

cm (*x)
No

pg (xx)
2π / 2
p2 (2222)

pmm (*2222)
Number of perpendicular reflections
Two

cmm (2*22)
One

pmg (22*)
None

pgg (22x)
2π / 3
p3 (333)

p3m1 (*333)

p31m (3*3)
2π / 4
p4 (442)

p4m (*442)

p4g (4*2)
2π / 6
p6 (632)

p6m (*632)