There are 3 Scroll Bars on the Form. The first Track Bar is stands for Red, second for Green and third for Blue, depends on the position of indicator the background color of form should be changed in VB.NET.

Public Class Form1
    Private Sub HScrollBarRed_Scroll(ByVal sender As System.Object, ByVal e As System.Windows.Forms.ScrollEventArgs) Handles HScrollBarRed.Scroll, HScrollBarGreen.Scroll, HScrollBarRed.Scroll
        Me.BackColor = Color.FromArgb(HScrollBarRed.Value, HScrollBarGreen.Value, HScrollBarBlue.Value)
    End Sub
End Class