Doo Icon

I've been experimenting with ways of making a checkmark more visually interesting. The UI of Doo features a stack of three cards fading in opacity. I'm attempting to riff on that design element using the purple color of the background.

My challenge is that the current mountain icon is a great metaphor for achievement, but is too abstract to read as reminders. The checkmark sets proper expectations, but is overused and has less personality.

Thoughts welcome!