Floating wishes

When I was a child there were no spongebob squearpants balloons for Reyes, they used to be beautiful and crazy colored balloons!  You could tie up your wishes and let them fly into the sky. I miss being a kid..

I couldn't believe my eyes when I saw that man selling the same balloons I loved back then, obviously I couldn't resist buy some of them and take pictures of their beautiful shapes, I still don't know how it's made, if someone knows how to do this... please let me know!!