 In some images , Hu employed a blind <unk> technique ( known as " <unk> designs " ( <unk> , <unk> ) or " <unk> blocks " ( <unk> , <unk> ) , using an <unk> , <unk> block to stamp designs onto paper . He used this to create white relief effects for clouds and for highlights on water or plants . This was a relatively new process , having been invented by Hu 's contemporary Wu <unk> , who was also a <unk> @-@ based publisher . Wu had used this technique for the first time in his book Wisteria Studio <unk> Paper ( <unk> <unk> <unk> , <unk> ) , published in <unk> . Both Hu and Wu used <unk> to create decorative writing papers , the sale of which provided a <unk> income for the Ten <unk> Studio . 
