The above code is from csim example code.
Question 1: in the above code t is defined, yet in plot2d t' is used. What does t' mean/represent?
Question 2: the 0*t' item to me means 0 (algebraically), what is the real meaning here?
t' is the transpose of t. 0*t' is multiplying every element of t with 0. I would recommend looking up matrix operations to understand similar code.
It would seem simpler to make a zero array and transpose it.