I am having difficulties defining the function f(x,y)=1 for 4<x<6, 4<y<6 and 0 Otherwise.

Here is what I have been trying:

f[x, y] = Piecewise[{{1, {{4 < x < 6}, {4 < y < 6}}}, {0, else}}]

This does not seem to work as when I plot it by doing:

Plot3D[{f[x,y]}, {x, 0, 10}, {y, 0, 10}]

nothing comes up.

Does anyone know how this can be done?

Thank you very much!