Normally, the points on the graph are connected by lines. If instead you would like to use symbols you can do something like this:

    data test.dat
    xcolumn 2
    ycolumn 3
    xlabel Cosine (Angle)
    ylabel Sine (Angle)
    symbolnumber 3
    symbolsize 0.06
    symbolevery 3
    title Scatter Plot

which would produce a graph like: