Implementing complex mathematical expressions using blocks each realizing a single basic math operation is not always desirable. Such constructions often lead to complex diagrams that are difficult to understand and debug. Moreover, any change in the mathematical expression being implemented requires a modification of the topology of the diagram. For this reason, Activate provides special blocks in which users can express input/output functions of the blocks as mathematical expressions provided as block parameter values. The three principal expression blocks in Activate are: the MathExpression, the MatrixExpression, and the OmlExpression blocks.