What is hidden in 3D image?
Brain Teasers
[3904] What is hidden in 3D image? - Stereogram - 3D Image - #brainteasers #stereogram #3Dimage
2017-05-16
Envelope machine patentIn 1849, the first U.S. patent for an envelope-making machine was issued to Jesse K. Park and Cornelius S. Watson of New York City (No. 6055). It was never used commercially, as it was shortly superceded by patents on improved machines by other inventors. It was treadle-operated and its mechanism included a stamper rod, gumming apparatus and folding apparatus. The patent model still exists in the collection of the National Postal Museum.« |
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