The article mentions 'The Ambassadors' by Hans Holbein The Younger. Around 15 years ago it received some restoration, to replace the restoration work believed t

The article mentions 'The Ambassadors' by Hans Holbein The Younger. Around 15 years ago it received some restoration, to replace the restoration work believed to be performed in the 19th Century. Until the recent work was completed the skull image was actually incorrect and the illusion did not work properly. But then again I'm not surprised, Holbein's portrait sketches show every individual hair on a subject's head.