Almost lost to history, these toys quite literally put quantum mechanics at one’s fingertips. In episode 35, Jean-François Gauvin from Université Laval in Canada, discusses how he came to understand the purpose and value of unique toy blocks that ended up on his desk at Harvard University in 2014 as the director of the Collection of Historical Scientific Instruments (CHSI). His article “Playing with Quantum Toys: Julian Schwinger’s Measurement Algebra and the Material Culture of Quantum Mechanics Pedagogy at Harvard in the 1960s” was published in March 2018 in Physics in Perspective.