Algodoo

This doesn't work. I pressed 1, 2, 3, 4, Enter as instructed, but it doesn't print anything.

Pretty neat. But you gotta stop uploading things at 1200Hz if it doesn't have to be that fast.

Ravenplucker - Did you get it to print? If so, how?

if you press "Enter key"after "1,2,3,4" , this prints '15'
It works 1200Hz only

I noticed that I have to press and hold the number keys for a certain time period, but not too long! That is not a good way to design keyboard entry. A user should be able to press a key quickly and have it store the key without having to hold it down for a certain time period. Same with the Enter key. If you could fix that problem, then it should work for everyone!

Thanks for your comment!
I fixed it

Yes, it works good now!

This is good