In Minecraft: Java Edition i can rotate each element of Armor stand as i wish. For example, i can rotate left arm using command /summon armor_stand ~ ~ ~ {ShowArms:1b,Pose:{LeftArm:[51f,145f,0f]}}. Lot's of things can be created using this, for example sword item in the block -
https://static.planetminecraft.com/files/resource_media/screenshot/1522/fp29am78973726_lrg.jpg

In pocket edition i can't. I can only set hardcoded poses, and it's really hard to achieve the result like on screenshot above