I don't know who erroneously taught you that a medium is always a one-way channel. In the creative sense, it's a cliche to talk about exploring something "thro

I don't know who erroneously taught you that a medium is always a one-way channel. In the creative sense, it's a cliche to talk about exploring something "through the medium of dance" or to refer to painting or drawing as a medium. The blackboard is a traditional mathematical medium.