Al, Thank you for getting me started with Elephant.

I've been studying your Basic Parametric Moebius.nod and finding it difficult to understand how it could produce a solid Moebius strip when my many attempts to do so (outside of Elephant) have failed when using Loft to make the complete strip in one go.

Eventually - it took a while - I realised that your node is not producing a solid Moebius strip - with only one surface - but a strip with two surfaces. See below.
Did you also do the moebius.nod? No problem with the strips in that however I've temporarily given up trying to fully understand the nod - it's too complex for me at the moment.
Mike.