No curved lines-A.E.F.H.I.K.L.M.N.T.V.W.X.Y.Z.
No straight lines-C.O.S.
No enclosed areas-C.E.F.G.H.I.J.K.L.M.N.S.T.U.V.W.X.Y.Z.
Horizontal symmetry-B.C.D.E.H.I.K.O.X.
Vertical symmetry-A.H.I.M.O.T.U.V.W.X.Y.
Roman numerals-C.D.I.L.M.V.X.
Just dots in Morse code-E.H.I.S.
Just dashes in Morse code-M.O.T.
Horizontal and vertical symmetry-H.I.O.X.
Look the same upside down-H.I.N.O.S.X.Z.
Can be drawn in one stroke-B.C.D.G.I.J.L.M.N.O.P.R.S.U.V.W.Z.
Capitals which look like lowercase-C.O.P.S.U.V.W.X.Z.
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