Short answers, pulled from the story.
The sheet measures 34 by 25 centimeters and was executed primarily with pen and light-brown ink. Traces of brown wash appear on the paper, which is larger than most of Leonardo's folio manuscript pages.
Leonardo's drawing is almost always dated to around 1490 during his first Milanese period. Two leading art historians differ in this respect; Martin Kemp gives 1490 while Carmen C. Bambach contends that the earliest possible date is 1488.
Leonardo made the scheme work by using the man's genitals as the center of the square and the navel as the center of the circle. Earlier drawings assumed the circle and square should be centered around the navel akin to Vitruvius's account.
It is kept on the fourth floor of the Gallerie dell'Accademia in a locked room because extended exposure to light would cause fading. The drawing has remained there since entering the collection in 1822.
An Italian court ruled in favor of the museum on the 17th of November 2022 and ordered the puzzle company to cease producing the product for commercial purposes. The court levied a fine of 1,500 euros for every day that the company failed to comply with the order.