weeeeeeeeeee

Graphics 640,480,0,0

Global mx:Float = -1
Global my:Float = -1
Global oldmx:Float
Global oldmy:Float

While Not KeyDown(KEY_ESCAPE)

	
	If MouseDown(1) Then
		If Mx And My > -1 Then
			oldMx = mx
			OldMy = my
		Else
			oldMx = MouseX()
			oldMy = MouseY()
		EndIf
		mx = MouseX()
		my = MouseY()
		For f:Int = 0 To 1 'draw it twice since we don't want to have flickering in fullscreen when we flip
			SetColor(255,100,255)
			DrawLine(oldMX, oldMY, mx, my)
			Flip
		Next
	Else
		mx = -1
		my = -1		
	EndIf
	
If MouseDown(1) Then
		If Mx And My > -1 Then
			oldMx = mx
			OldMy = my
		Else
			oldMx = MouseX()
			oldMy = MouseY()
		EndIf
		mx = MouseX()
		my = MouseY()
		For f:Int = 0 To 1 'draw it twice since we don't want to have flickering in fullscreen when we flip
			SetColor(255,255,255)
			DrawLine(oldMX, oldMY, mx, my)
			Flip
		Next
	Else
		mx = -1
		my = -1		
	EndIf

If MouseDown(1) Then
		If Mx And My > -1 Then
			oldMx = mx
			OldMy = my
		Else
			oldMx = MouseX()
			oldMy = MouseY()
		EndIf
		mx = MouseX()
		my = MouseY()
		For f:Int = 0 To 1 'draw it twice since we don't want to have flickering in fullscreen when we flip
			SetColor(0,0,255)
			DrawLine(oldMX, oldMY, mx, my)
			Flip
		Next
	Else
		mx = -1
		my = -1		
	EndIf

If MouseDown(1) Then
		If Mx And My > -1 Then
			oldMx = mx
			OldMy = my
		Else
			oldMx = MouseX()
			oldMy = MouseY()
		EndIf
		mx = MouseX()
		my = MouseY()
		For f:Int = 0 To 1 'draw it twice since we don't want to have flickering in fullscreen when we flip
			SetColor(255,0,0)
			DrawLine(oldMX, oldMY, mx, my)
			Flip
		Next
	Else
		mx = -1
		my = -1		
	EndIf

	FlushMem
Wend
End

*EDIT*

I see you used the code sample I posted, but you really need to try and cut that code down a touch, repeating the same thing each time you want to change the colour is not the best way to do that.

Graphics 640,480,0,0

Type TRGB
	Field Red:Int
	Field Green:Int
	Field Blue:Int
End Type

Global mx:Float = -1
Global my:Float = -1
Global oldmx:Float
Global oldmy:Float
Global colours:TRGB[4] 'create an array 4 elements long with a TRGB type in each
Global colourindex : Int = 0


'randomly assign colours, but could just as easily manually set any colours we want
SeedRnd(MilliSecs()) ' the most common way of ensuring we get a truly random number
For a:Int = 0 To 3
	colours[a] = New TRGB
	colours[a].Red = Rand(128,255)
	colours[a].Green = Rand(128,255)
	colours[a].Blue = Rand(128,255)
Next


While Not KeyDown(KEY_ESCAPE)

	
	If MouseDown(1) Then
		If Mx And My > -1 Then
			oldMx = mx
			OldMy = my
		Else
			oldMx = MouseX()
			oldMy = MouseY()
		EndIf
		mx = MouseX()
		my = MouseY()
		For f:Int = 0 To 1 'draw it twice since we don't want to have flickering in fullscreen when we flip
			SetColor(colours[colourindex].Red,colours[colourindex].Green,colours[colourindex].Blue)
			DrawLine(oldMX, oldMY, mx, my)
			Flip
		Next
		colourindex:+1
		If colourindex>3 Then colourindex = 0
	Else
		mx = -1
		my = -1		
	EndIf

	FlushMem
Wend
End

why is this in the showcase ?

Because he acheived something and wants to show it off?
My guess being he's about 12, new to programming and getting excited about getting a working app.
remember what that was like?

Nice :)

Nice colors! Dig it! :)