Can you think of words...
with horizontal symmetry?
with vertical symmetry?
with 180 degrees rotation symmetry?
What are the LONGEST words in each category? (Common words are preferred.)
Theres quite a few of these but as you prefer common words this is what i've come up with.
the longest common word I can think of with horizontal symmetry is CHECKBOOK.
Vertical symmetry-otto, tool, maam
Rotational symmetry-SWIM, though all the letters in ONIONS
possess independent rotational symmetry. BID has horizontal symmetry when written in caps and vertical symmetry when written in lower case, bid.