In previous file the file was red from the start and you could simply drag it without thinking until it turns green. You can stimulate thinking by introducing a button submit so that point starts blue and the control by dynamic coloring will only be done after clicking on this button.

Start from previous file and make following changes:[br][list][*][b]submit[/b]: [br]- Define a number submit = 0.[br]- Create a button with the script command [code]SetValue[submit,1][/code][br][/*][*][b]Dynamic colors of P[/b]: Change the dynamic colors of P as follows[br]Red: [code]If(submit ≟ 1 ∧ (P ≠ Sol), 1, 0)[/code][br]Green: [code]If(submit ≟ 1 ∧ (P == Sol), 1, 0)[br][/code][br]Blue: [code]0[/code][/*][*][b]new exercise[/b]: add in the script of the button the command [code]SetValue[submit,0][/code][/*][/list]