Teasing apart multi-scale interactions

In the previous exercise, you fit the following model:

tensor_mod <- gam(cadmium ~ te(x, y, elev), 
                  data = meuse, method = "REML")

In this exercise, you will fit a model with smooths and tensor interactions to separate out the independent and interacting effects of variables.

Convert the above model such that x and y interact on the same scale, the effect elev is a separate smooth, and the interaction of all three on different scales is a separate term.
Summarize and plot the model.