 During this period Lissitzky proceeded to develop a suprematist style of his own , a series of abstract , geometric paintings which he called Proun ( pronounced " pro @-@ oon " ) . The exact meaning of " Proun " was never fully revealed , with some suggesting that it is a contraction of <unk> <unk> ( designed by UNOVIS ) or <unk> <unk> <unk> ( Design for the confirmation of the new ) . Later , Lissitzky defined them ambiguously as " the station where one changes from painting to architecture . " 
