All blocks in a model must be sized such that the icon is completely visible and recognizable. In particular, any displayed text (for example, tunable parameters, file names, or equations) in the icon must be readable.
This guideline requires that you resize blocks with variable icons or blocks with a variable number of inputs and outputs. In some cases, it may not be practical or desirable to resize the icon of a subsystem block so that all of the input and output names within it are readable. In such cases, you may hide the names in the icon by using a mask or by hiding the names in the subsystem associated with the icon. If you do this, the signal lines coming into and out of the subsystem block should be clearly labeled in close proximity to the block.