Multiclass plot reading

in the week3 final assignment lab, in the neural network section, first we create a complex model. And after we compile the model, we found the J_cv is high, but I am having trouble to read the graph, why we are having extra circle here?

isn’t it should be a line to separate all the categories without any small circles like the graph of the small neural network model

The top two figures show overfitting.

The curves are lines of constant cost. if you get a non-uniform curve, it means the cost varies strongly around the area of the boundary. That is characteristic of overfitting.