Find the minimum number of straight lines required to make the given figure.
17
18
21
20
19
Horizontal lines are IK, AB, HG and DC i.e. 4 in number.
Vertical lines are AD, EH, JM, FG and BC i.e. 5 in number.
Slanting lines are IE, JE, JF, KF, DE, DH, FC and GC i.e. 8 in number.
So, total lines = 4 + 5 + 8 = 17