Moving one of 200 cubes?

Hi,
I've got a little example here, it creates 200 cubes and it could be even more:

Graphics3D 800,600
cam=CreateCamera()
PositionEntity cam,0,0,10
light=CreateLight()

For i=0 To 200
create_cube(i)
Next

While Not KeyHit(1)
TurnEntity cam,0,-0.1,0

RenderWorld()
Flip
Wend

Type Cube
Field cube_mesh%
End Type

Function create_cube(pos)
a.Cube= New Cube
a\cube_mesh=CreateCube()

PositionEntity a\cube_mesh,10,0,pos*5
End Function

Pretty simple actually. But how can I move or turn etc. for example the seventh cube out of these 200?