how to complete this question?

The input is expected to consist of height + 1 lines of length + 1 numbers in {0...15}, where length
is at least equal to 4 and at most equal to 50 and height is at least equal to 2 and at most equal to 16,
with possibly lines consisting of spaces only that will be ignored and with possibly spaces anywhere on
the lines with digits. The xth digit n of the yth line, with 0 <=x<= length and 0 <= y <= height,
 is to be associated with a point situated x * 0:2 cm to the right and y * 0.2 cm below an origin,
 is to be connected to the point 0.2 cm above if the rightmost digit of n is 1,
 is to be connected to the point 0.2 cm above and 0.2 cm to the right if the second rightmost digit
of n is 1,
 is to be connected to the point 0.2 cm to the right if the third rightmost digit of n is 1, and
 is to be connected to the point 0.2 cm to the right and 0.2 cm below if the fourth rightmost digit
of n is 1.
To qualify as a frieze, the input is further constrained to t in a rectangle of length length * 0.2 cm and
of height heigth * 0.2 cm, with horizontal lines of length length at the top and at the bottom, identical
vertical borders at both ends, no crossing segments connecting pairs of neighbours inside the rectangle,
and a pattern of integral period at least equal to 2 that is fully repeated at least twice in the horizontal
dimension.