Determine the point groups for a. A triangular prism b. A plus sign c. A...

Determine the point groups for

a. A triangular prism

b. A plus sign

c. A t-shirt with the letter T on the front

d. Set of three wind turbine blades

e. A spade design (as on a deck of playing cards)

f. A sand dollar

g. Flying Mercury sculpture, by Giambologna at the Louvre in Paris, France

h. An octahedron with one blue face, the others yellow

i. A hula hoop

j. A coiled spring