Effects of various RGBA values

[Lunatic3]

How you draw a rectangle? do you know that? The same way you can file a rectangle. For example in a paint event:

Dim br As New SolidBrush(Color.FromArgb(a, r, g, b))
e.Graphics.FillRectangle(br, New RectangleF(0, 0, 100, 100))