Heidoscop-Anastigmat (viewfinder lens Rolleiflex)

Does some member has an idea about the scheme of the 3 lenses in this viewing lens of the Rolleiflex / Rolleicord?
(some pre-owner of one of my flexes has apparently disassembled the lens and didn't put the 2nd and 3rd lens back in right order, since it doesn't focus too well)

thanks
Ron

The front and back lenses are different sizes, yes? The curved surface goes to the outside.

The middle lens has, I think!!- the deeper curve to the back. Rub lightly with a fingernail and you can feel the difference in the curve, small but real.

The front spacer is, again, obvious. The rear spacer has, I think!!- the bevel to the front.

There are the two variables- center lens orientation and rear spacer orientation. So at worst you have to reassemble three times if the first one doesn't give a clear image.

Manual grab-

Many thanks Daniel, indeed this makes very clear how the back lens should be set. The middle lens is then up for a test; so effectively 2 tries ....