The Diag's ''M'' Don't step on it... We've probably all heard it: step on the ''M'' before your first blue book exam and you're destined to fail it. With testimonies from both sides, it's hard to say whether or not this myth has any merit. The tradition behind the Diag's block M seal, however, is widely respected and deeply rooted. Originally crafted in 1922 by a mastermason in the Plant department to commemorate his work at the U, the original brick and mortar ''M'' survived until a new walkway needed to be placed through the Diag in 1952. The class of 1953 replaced the original seal with a new brass one, which is still there today.