Playful Learning Environments - © 2023 President and Fellows of Harvard College.

The thing that hit into the zip line, You know, the black part at the bottom. [...] T: Oh, so you saw that there are two wheels inside and that when it hits this side the wheels roll backwards. [...] Is that what you meant? C4: I have seen it, how the wheels inside, when they hit into the wheels turn backwards and it moves backward. [...] T: Oh, so you saw that there are two wheels inside and that when it hits this side the wheels roll backwards. [...] Is that what you meant? T: Oh, so you saw that there are two wheels inside and that when it hits this side the wheels roll backwards.