I'm looking for a pattern for toggling between different periods of time. Currently I've prototyped an example which is a single button that, when tapped, will cycle through 3 time periods: by month, by quarter and by week. Cycling through the time periods adjusts a goal number that is set by the user (ie 100/month, 300/quarter, 25/week). I'm having trouble finding other examples of a pattern similar to what I've mocked up.
We've done a little but of user testing with this example, and they seem to be confused at first but immediately understand the functionality after tapping it. Is there something that I can do to add more affordance to this interaction, whether it's a different button/toggle style, an added icon, etc? Or is there a completely different, better pattern altogether? Screenshots or links to established patterns are greatly appreciated!