程序代码：

Option Explicit
'在窗体上放一个Picture1，在Picture1里放一个Shape1
'DEBUG是放一个 Label1 ，拉高一点，需要显示5行数据，同时下面 语句注释去掉

Dim qx As Long, qy As Long          '球坐标
Dim qxb As Long, qyb As Long        '变化量

Dim r1 As Long, g1 As Long, b1 As Long      '颜色
Dim rb As Long, gb As Long, bb As Long      '颜色变化

Private Sub Form_Load()
Timer1.Interval = 50       '定时器
Shape1.Shape = 3            '圆形
Shape1.FillStyle = 0        '填充模式

qx = Shape1.Left
qy = Shape1.Top
qxb = 120
qyb = 120

rb = 16
gb = 16
bb = 16

End Sub

Private Sub Timer1_Timer()

If cb(b1, bb, 0, 255) Then
    If cb(g1, gb, 0, 255) Then
        Call cb(r1, rb, 0, 255)
    End If
End If

Picture1.BackColor = RGB(r1, g1, b1)
Shape1.FillColor = RGB(255 - r1, 255 - g1, 255 - b1) '小球我这里使用补色

Call cb(qx, qxb, 0, Picture1.ScaleWidth - Shape1.Width)
Call cb(qy, qyb, 0, Picture1.ScaleHeight - Shape1.Height)

Shape1.Move qx, qy

'DEBUG
Label1.Caption = "X:" & qx & vbCrLf & "Y:" & qy & vbCrLf & "R:" & r1 & vbCrLf & "G:" & g1 & vbCrLf & "B:" & b1

End Sub

Public Function cb(C As Long, b As Long, CS As Long, CE As Long) As Boolean     '计算过程，超限会设置标志位
'c 计算变量 ,b 变化量,CS 最小值,CE 最大值
'变化量是在正负之间跳动

cb = False
C = C + b
If C > CE Then
    C = CE
    b = -b
    cb = True
ElseIf C < CS Then
    C = CS
    b = -b
    cb = True
End If
End Function