Butterfly effect

i've been doing some research about this and i came up to this code:

read this first:
there are two universes; in universe 1 the balls are blue, in universe 2 the balls are green. both universes does not affect each other!

the green and the blue universes start at exactly the same beginning conditions, except that in the green one i moved ONE little ball ONE pixel.
and now watch, how this tiny change makes the differences of our life!!

Graphics 1024, 768, 32, 2
SetBuffer BackBuffer()
SeedRnd MilliSecs()

Type Ball1
	Field x#, y#
	Field vx#, vy#
	Field oldx#, oldy#
	Field fric#, mass#
End Type
Type Ball2
	Field x#, y#
	Field vx#, vy#
	Field oldx#, oldy#
	Field fric#, mass#
End Type

;Many balls
For i = 1 To 20
	x# = Rand(0, GraphicsWidth())
	y# = Rand(0, GraphicsHeight())
	fric# = Rnd(.9, 1)
	mass# = Rnd(1, 30)
	CreateBall1(x#, y#, fric#, mass#)
	CreateBall2(x#, y#, fric#, mass#)
Next
;The center ball
CreateBall1(GraphicsWidth() / 2, GraphicsHeight() / 2, 0, 100)
CreateBall2(GraphicsWidth() / 2, GraphicsHeight() / 2, 0, 100)
;The shifted ball
CreateBall1(100, 100, 0, 10)
CreateBall2(100, 101, 0, 10)

speed# = 1
Repeat
	Cls
	order = 1 - order
	If order Then
		UpdateBalls1(speed#)
		UpdateBalls2(speed#)
	Else
		UpdateBalls2(speed#)
		UpdateBalls1(speed#)
	EndIf
	Flip
Until KeyHit(1)
End

Function CreateBall1(x#, y#, fric#, mass#)
b.Ball1 = New Ball1
b\x# = x#
b\y# = y#
b\oldx# = b\x#
b\oldy# = b\y#
b\fric# = fric#
b\mass# = mass#
End Function

Function CreateBall2(x#, y#, fric#, mass#)
b.Ball2 = New Ball2
b\x# = x#
b\y# = y#
b\oldx# = b\x#
b\oldy# = b\y#
b\fric# = fric#
b\mass# = mass#
End Function

Function UpdateBalls1(speed# = 1)
Color 128, 128, 255
For b.Ball1 = Each Ball1
	b\vy# = 0
	b\vx# = 0
	For b2.Ball1 = Each Ball1
		xdiff# = b2\x# - b\x#
		ydiff# = b2\y# - b\y#
		dis# = Sqr(xdiff# * xdiff# + ydiff# * ydiff#)
		If Abs(dis#) > 0 Then
			b\vx# = b\vx# + (xdiff# / dis#) / (dis# * b\mass# / 10)
			b\vy# = b\vy# + (ydiff# / dis#) / (dis# * b\mass# / 10)
		End If
	Next
	tx# = b\x#
	ty# = b\y#
	b\x# = b\x# + b\x# * b\fric# - b\oldx# * b\fric# + b\vx# * speed#
	b\y# = b\y# + b\y# * b\fric# - b\oldy# * b\fric# + b\vy# * speed#
	If b\x# < 0 Then b\x# = 0
	If b\x# > GraphicsWidth() Then b\x# = GraphicsWidth()
	If b\y# < 0 Then b\y# = 0
	If b\y# > GraphicsHeight() Then b\y# = GraphicsHeight()
	b\oldx# = tx#
	b\oldy# = ty#
	
	Oval b\x# - b\mass# / 2, b\y# - b\mass# / 2, b\mass#, b\mass#
Next
End Function

Function UpdateBalls2(speed# = 1)
Color 128, 255, 128
For b.Ball2 = Each Ball2
	b\vy# = 0
	b\vx# = 0
	For b2.Ball2 = Each Ball2
		xdiff# = b2\x# - b\x#
		ydiff# = b2\y# - b\y#
		dis# = Sqr(xdiff# * xdiff# + ydiff# * ydiff#)
		If Abs(dis#) > 0 Then
			b\vx# = b\vx# + (xdiff# / dis#) / (dis# * b\mass# / 10)
			b\vy# = b\vy# + (ydiff# / dis#) / (dis# * b\mass# / 10)
		End If
	Next
	tx# = b\x#
	ty# = b\y#
	b\x# = b\x# + b\x# * b\fric# - b\oldx# * b\fric# + b\vx# * speed#
	b\y# = b\y# + b\y# * b\fric# - b\oldy# * b\fric# + b\vy# * speed#
	If b\x# < 0 Then b\x# = 0
	If b\x# > GraphicsWidth() Then b\x# = GraphicsWidth()
	If b\y# < 0 Then b\y# = 0
	If b\y# > GraphicsHeight() Then b\y# = GraphicsHeight()
	b\oldx# = tx#
	b\oldy# = ty#
	
	Oval b\x# - b\mass# / 2, b\y# - b\mass# / 2, b\mass#, b\mass#
Next
End Function

btw: the basic verlet code is not by myself....