Task: Question Answering
Input (English): A mid-1950s construction worker involved in the demolition of the "J. C. Wilber Building" finds a box inside a cornerstone. He opens it to find a commemorative document dated April 16, 1892. Inside is also a singing, dancing frog, complete with top hat and cane. After the frog suddenly performs a musical number there on the spot, the man tries exploiting the frog's talents for money. However, the frog refuses to perform for any individual other than its owner, instead devolving into croaking in the presence of others. The man frantically tries to demonstrate the frog's abilities to the outside world, first by trying to get a talent agent to accept him, then by renting out a theater for it to perform in, all to no avail.After these failed attempts to profit from the frog, the man becomes destitute and is living on a park bench, where the frog still performs only for him. A policeman overhears this and approaches the man for disturbing the peace, but when the man points out the frog as having done the singing, the officer takes the man into custody. He is committed to a psychiatric hospital along with the frog, who continues serenading the hapless patient. Following his release, the haggard, broken man, carrying the frog inside the box, spies the construction site where he originally found the box, and dumps it into the cornerstone of the future "Tregoweth Brown Building" before sneaking away. The timeline then jumps to 2056 (101 years after the cartoon's debut). The Brown Building is being demolished using futuristic ray guns, and the box with the frog is discovered yet again by a 21st-century demolition man, who, after envisioning riches as well, absconds with the frog to start the process once again., Question: What was found inside a cornerstone?
Output (English): Answer: box