An intriguing challenge with physics

Dr. is it something like this?

SetBuffer BackBuffer()

Type arm
	Field x#,y#
	Field s#,l#
	Field parent.arm
End Type

parm.arm = Null

;
; s# indicates how fast each joint can turn
s# = 0.02

For i = 0 To 5
	arm.arm = New arm
	arm\parent = parm
	If parm = Null
		arm\x = 200
		arm\y = 150
	End If
	arm\l	= 20.0
	arm\s	= s#
	
	;
	; Set the next arm's parent to be this one
	parm = arm
	;
	; Increase s# for each new arm
	s# = s# * 1.5
Next

Repeat

	Cls
	
	a#	= a+2.0
	tx# = MouseX()
	ty# = MouseY()

	For arm.arm = Each arm
		If arm\parent<>Null
			;
			; Vector between this arm's joint and the mouse
			dx# = tx-arm\x
			dy# = ty-arm\y
			d# = Sqr(dx*dx + dy*dy)
			If d = 0 Then d = 1.0
			dx# = arm\parent\x+((dx/d)*arm\l)
			dy# = arm\parent\y+((dy/d)*arm\l)
		
			;
			; Turn the arm to be closer to the mouse
			arm\x = arm\x-(arm\parent\x-dx)*arm\s
			arm\y = arm\y-(arm\parent\y-dy)*arm\s
			
			;
			; Make sure the arm doesn't change length
			dx# = arm\x-arm\parent\x
			dy# = arm\y-arm\parent\y 
			d# = Sqr(dx*dx + dy*dy)
			If d = 0 Then d = 1.0			
			arm\x# = arm\parent\x+((dx/d)*arm\l)
			arm\y# = arm\parent\y+((dy/d)*arm\l)
			
			;
			; Draw the arm
			Oval arm\x-2,arm\y-2,5,5,True
			Line arm\x,arm\y,arm\parent\x,arm\parent\y
		Else
			;
			; Just move the first joint around in a circle
			arm\x = 200+(Sin(a)*20.0)
			arm\y = 150+(Cos(a)*20.0)
			Oval arm\x-6,arm\y-6,13,13,False
			Oval arm\x-2,arm\y-2,5,5,True
		End If
	Next
	
	Flip
	
Until KeyHit(1)
End

And the funny thing is I don't really know what I'm doing either :) I don't really know about any books, just get some basic maths books about vectors, they will get you far if you are interested in it!