Global Container Field with four repetitions, colored buttons pasted into in Browse Mode.
Value Number field
Calculation Field based on Value Number with Container Result of one of the repetitions.
I suspect that in your original calculation field, you didn't select "container" in the "result" drop down as David shows in his excellent screen shot.
BTW, if you want to show checkmark appear and disappear, you can also do this with conditional formatting and layout text taken from a symbol font to show as the check or "tickmark". Setting the font size to 500 makes it disappear.
Oh, and the ButtonStoplightValue was set as a button that would increment value to change button color.
And there were five instances of the stoplight buttons in an array for a unlabeled value set for searching.
The Computer Guy, Seattle