The attached diagrams show a rectangular plate held by joints defined by pins and links.
Which ones have:
A) Static determinancy
D) Overconstraint in some DoF,
Underconstraint in others
Some definitions can be found at web page http://ecow.engr.wisc.edu/cgi-bin/get/ema/201/hoerr/lecturenot/l1953.pdf
The diagrams in ...
The solution discusses the assessment of static determinacy.