3D chalk art — also known as street art is an optical illusion. The creations can be interactive and entertaining; people love to see them being created and often pose in them for photos.
Chalk drawings can be sealed to last or painted to make them permanent but often the chalk just washes away!
The drawings generally only work from one viewpoint (see the first photograph below) otherwise the image appears strangely distorted (the second photograph).
Banyule Council has been providing creative events and activities. Currently it is ‘Pop up sand sculptures’. Their website is well worth a visit. https://www.banyule.vic.gov.au