Steelwork illusion

Linking with my theme of impossible I have found a picture by Deskarati. Initially it seems like a normal photo of by gone era of health and safety free workers relaxing on a high grid of steel girders. However it is only after you look at it in more depth that you realise the steelwork that the centre figure is relaxing on is an impossibility. This is a very clever real life take on what is usually a very simply drawn illusion.