Why Are There Coins Embedded Outside The Ford Museum?

I never noticed this little Easter egg outside of the Gerald R. Ford Presidential Museum before, have you?

A post to the Grand Rapids subreddit shows that some random person wanted to leave something behind to honor the late, great Gerald R. Ford at the place built in his adopted home town to honor him.

The only person to serve as Vice President and President of the United States without having been elected to either position, Ford was an unique individual who served in the United States Congress for 25 years before he stepped in to fill in first for Vice President Spiro Agnew after he resigned due to scandal, and then became the Commander in Chief a few years later when President Nixon did the same.

Outside the Presidential Museum in Ah-Nab-Awen Park are five coins glued the concrete. A quarter, a dime and three pennies. Does anyone recognize what these coins represent?

Bueller? Bueller? Bueller? Anyone?

The total of the coins is 38 cents, which is a homage to Ford, who was our 38th President. As noted by a commenter to the Reddit thread shown below, the dates on the coins are from the early 2000s, meaning that someone glued these coins well after the construction and dedication of the Library and Museum.

Now that we know why the coins are there, can someone please explain the giant red shirt button that is outside the Museum? Yes, I know it's part of the playground, but it's the only playground I know that has a shirt button in it.