Typewatching by elbows. It's real, it works, it's scienz!
ISTJ: Always has elbows covered, due to a need for propriety. usually angular. Will develop a rigid classification system for elbows. Serial killer ISTJs will file elbow parts in the appropriate bin.
ISFJ: Covers elbows as well, except in more gay colors or "kitten" designs rather than drab winter hues. Makes sure one's children know how to properly and respectfully treat elbows.
ESTJ: Wears large spikes on elbows, to gut people in their way.
ENTJ: Wears large poisoned spikes on elbows, just to be sure that death occurs.
ESFP: Elbows move energetically, just like the ESFP is constantly moving moving moving... whether on the dance floor, in bed getting wild, or jumping off the neighbor's roof in order to film a cool stunt for Jackass.
ENFP: Like the ESFP, except there's more chance the footage will be used to aggressively promote world peace or for some artsy-fartsy college project.
INTP: Elbows are not seen because they are hidden behind the INTP's computer monitor or stack of library books. INTP will be able to discuss elbows of alien races from any sci-fi TV series ever shown.
INFP: Elbows are gaily decorated in flowing ribbon and occasionally the bizarre yarn ornament, flitting around the room. (If people complain, the INFP will openly apologize while inwardly experiencing deep resentment -- elbows will flush red in indignation.) Exception: OrangeAppled
INFJ: Elbows are never placed on the table. Elbows are also used to jab people in the gut or under the chin if people get within the minimally accepted body space. No one else knows the secrets of the INFJ's elbows.
INTJ: Elbows can be used to take over the world. (I can't imagine how, but if it's possible, they will find a way to do it -- think "Sorcerer's Apprentice" but with elbows, not brooms -- "It lives, it lives -- mua ha ha ha!")
ENTP: "1001 uses for an attached elbow" is the book the ENTP could write, except for the fact that ENTPs never finish writing anything.
ESTP: "1001 uses for an attached elbow" is the book the ESTP could sell, if they can con someone else to write it for them (perhaps an OCD ENTP?)
ENFJ: Elbows are generally more flattened, as their arms are around someone. Will nurture children to march to the beat of their own elbows.
ISTP: Elbows have blood on them. (Whose, it's hard to tell; ISTP will be indifferent or oblivious.)
ISFP: Elbows are usually covered by happy doggie drool or axle grease. The only rule here is that there are no rules about elbows.
ESFJ: Elbows are always in movement, because there's always work to be done! Elbows that are improper will be soundly slapped but still accepted.
Additions, alterations, observations permitted.