Draw graph connecting series of points on masked subsystem icon
plot(Y) plots, for a vector Y, each element against its index. If Y is a matrix, it plots each column of the matrix as though it were a vector.
plot(X1,Y1,X2,Y2,...) plots the vectors Y1 against X1, Y2 against X2, and so on. Vector pairs must be the same length and the list must consist of an even number of vectors.
Plot commands can include NaN and inf values. When Simulink® software encounters NaNs or infs, it stops drawing, and then begins redrawing at the next numbers that are not NaN or inf. The appearance of the plot on the icon depends on the units defined by the Icon units option in the Mask Editor.
When you have not defined values for the parameters used in the drawing commands (for example, when you first create the mask, but have not yet entered values in the Mask Settings dialog box)
When you enter a masked block parameter or drawing command incorrectly
plot([0 1 5], [0 0 4])
generates the plot that appears on the icon for the Ramp block, in the Sources library.