enemy wave.. almost there HELP!

Ok I got an enemy wave, using Cos to move on the y and atan2 to set their angle but... as they are now they are all in a line when they are created, when they are created i need them to all ready be in a nice wavey line, but i cant figure it out, ive tried changing lots of things but what every i try they move off the line they need to follow. Can ya help??? I know i need to set some vars when im creating the types but ive tried lots with no success.

!!NO MEDIA NEEDED!!, copy'n'paste and run.

Graphics 640,480,0,60
	
Global Ltemp:TList=New TList	
Type Ttemp
	Field x#,y# Field waveinc#
	Field vx#,vy#,angle
End Type

make(8) ' make 8 ships
'===================================

Repeat ; Cls

	Update()
	
	DrawLine 0,240,640,240,1		' centre point line
	DrawLine 0,240+64,640,240+64,1 ' top boundry
	DrawLine 0,240-64,640,240-64,1 ' bottom boundry

FlushMem ; Flip ; Until KeyDown(KEY_ESCAPE)=True ; End

'====================================

Function Update()

	For t:Ttemp=EachIn Ltemp
		
		
		If t.x>640 Then t.x=0 ' loop through the screen
		
		t.angle = ATan2((t.Y+t.VY) - t.Y , (t.X+t.VX) - t.X) ' get angle
		
		t.waveinc:+1
		t.vy=Cos(t.waveinc)*0.8
		
		t.y:+t.vy
		t.x:+t.vx ' ,move on the x
		
		SetRotation t.angle
			SetColor 255,255,255 ; DrawRect t.x-16,t.y-8,32,16
		SetRotation 0
	
	Next

End Function

'------

Function make(count)

	For i=1 To count
		
		t:Ttemp=New Ttemp
		ListAddLast Ltemp,t
			t.x=320-(i*64)
			t.y=240
			t.vx=1
	Next
	
End Function