Use a variable to add the costs of premium features that are selected or deselected using an iOS switch component. See a video of how to do this step-by-step in this webinar: https://support.proto.io/hc/en-us/articles/115001585411-Model-advanced-prototypes-that-use-variables-part-II TAGS: variables variable math addition switch switches fire an items event

I used the Sketch "Delicious" free UI Kit for a food recipes app. It includes 11 pixel-perfect screens. I just added Proto.io interactions and created a great prototype! This Delicious UI Kit was designed by Robert Anitei Sketch source: https://www.sketchappsources.com/free-source/1765-delicious-ui-kit-sketch-freebie-resource.html

A project which simulates a collision between 2 objects. Freely drag the objects onto each other in order to have their core color change when colliding.

This app allows you to call loved one and the emergency services in to clicks. If you travel overseas this app is for you. It tells you tips of what to do in certain situations and you are able to enable GPS so the emergency services are able to see where you are.

Music player with a slider controlling volume of Music playing.

Music App project Design Credits: https://www.sketchappsources.com/free-source/2847-apple-music-app-sketch-freebie-resource.html