Above:Version by Mark Longridge
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Yes, it glows in the dark!
Although the idea of placing numbers on a cube is not new, getting them to glow in the dark is.
The stickers glow a typical glow-in-the-dark green colour when "charged" with bright light.
Mark says his original idea was to use six different glow in the dark colours, but was only able to find two.
It is unknown when Mr. Longridge presented his variant. In 2010 Olivér Nagy presented his version which gives an upper bound.
Thank you to the following people for their assistance in helping collect the information on this page: Sandy.
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