The apps
Each one so far runs as a single file your browser opens, and keeps working with the internet switched off; the larger ones are served here as a few files from this site, and from nowhere else. No account, no adverts, nothing collected, nothing sent anywhere. They are free and will stay free.
How Far?
Out from the Sun one stop at a time, to scale, all the way to the nearest star.
The Long Way Round
The orbits in three dimensions. Turn them side-on and see that it is all one flat sheet.
Who Could Call?
The telephone from Bell's first sentence to the newest phones, and at every step, how many people could call, out of everyone alive.