[D] Why do we always illustrate and depict the Loss Functions of Neural Networks as Non-Convex?

Why do we always illustrate and depict the Loss Functions of Neural Networks as Non-Convex?

By doing a quick Google Images Search of "Loss Functions for Neural Networks" - we are generally shown the same types of pictures. The Loss Function is generally illustrated as a colorful and wavy/bumpy surface :

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https://i.stack.imgur.com/wk9sd.jpg

My Question: Does anyone know why we often use these kinds of illustrations? My impression is that we want to point out that the Loss Functions for …

machinelearning networks neural networks