At first, Mathias uses the brushes to paint the paper but soon he stacks them away and dunks his whole hands in the jars and proceeds to use his hands to paint with.
Mathias's sensory exploration enhances his brain development. Language solidifies as he feels the paint; it is wet, cold, sticky, smooth, thick ...
He notices the cause and effect of mixing the colours and witnesses the paper ripping when over worked.
His early experiences are interchangeable and will continues to expand as he plays in the sand, the water, the play dough, the mud kitchen etc.
Mathias is like a "sponge" gathering information about the world he lives in.