a.k.a. Ten Block Puzzle, Traffic Cop Tangle
George E. Schweig and Son, Philadelphia PA.
(cardboard box and ten wood pieces, 4 x 3.25 x 1/2 inches)

Exchange the two 2x2 pieces. Described on pages 12-13 of the 1942 Filipiak book (which gives a 55 rectilinear moves / 70 straight-line moves solution). Below are all of the steps that move a 2x2 piece in a solution of 47 rectilinear moves (55 straight-line moves) that is presented in Hordern's book (pieces numbered the same with M,W instead of A,B):

Old Handwritten Solution
This solution is on the inside of the green cover shown on the preceding page.