Here is very basic one, but in my opinion very powerful because it's not only a visual explanation of a concept but also asks for visualising or imagining a real object depicting the concept:

Neophytes sometimes have a hard time understanding very basic concepts like mean, median and mode.

So, for helping them to better grasp the idea of mean: "Take this skewed distribution and do a 3D print of it, in plastic, or carve it in wood, so now you have a real object in your hands. Try to balance it using just one finger... the mean is the only point where you can do that."

Here is very basic one, but in my opinion very powerful because it's not only a visual explanation of a concept but also asks for visualising or imagining a real object depicting the concept:

Neophytes sometimes have a hard time understanding very basic concepts like mean, median and mode.

So, for helping them to better grasp the idea of mean:

Take this skewed distribution and do a 3D print of it, in plastic, or carve it in wood, so now you have a real object in your hands. Try to balance it using just one finger... the mean is the only point where you can do that.