Block Inputs: Scalar, vector, and matrix input.
The merge block examines 
(Boolean signal) to determine the
output signal. The letters
b, t, and f on the input connector tabs
stand for Boolean, True, and False.
The merge block is particularly well-suited for performing if-then-else decisions.
Label: Indicates a user-defined block label.
1. Simple merge
Consider the equation:
If y = 2, then z = 5, else z = 2.5
This equation can be realized as:
2. Cascade merge
Consider the equation:
If x = 1 and y = 2, then q = z, else q = 0
where (if y = 2, then z = 5, else z = 2.5). This logical relation can be realized as shown below.
