The following is an example that displays 5 one-dimensional random walks of 200 steps:
y = cumsum(rand(200,5) - 0.5); plot(y) legend('1', '2', '3', '4', '5') title('random walks')
In the above code,
y is a matrix of 5 columns, each of length 200. Since
x is omitted, it defaults to the row numbers of
y (equivalent to using
x=1:200 as the x-axis). This way the
plot function plots multiple y-vectors against the same x-vector, each using a different color automatically.