Recyclable Art

I swear there is almost always something going on at náměstí Svobody.  I went to DM today to pick up a few things and saw this big "number one" filled with plastic recyclables.  

I didn't see a sign or anything that gave any details about it so I guess it either (a) isn't finished yet or (b) it's up to the individual to figure it out.  I wonder how long it will be up for?

Update:  It was gone sometime the next week.