He has used a mixture of Mosaic, collage and felt-tip pen.

他混合使用了马赛克、拼贴画和毡头笔。

youdao

Draw the basic Outlines in black felt-tip pen (see FIG. 4).

用黑色毡头笔画出基本轮廓(见图4)。

youdao

In many cases the signature was photocopied or printed, then traced over with a felt-tip pen.

在许多情形下，签名先是影印或印刷出来，再用记号笔在上面描绘。

youdao

Drawn on a piece of paper, the spokesman said it was "full of the pop art motifs we have now come to recognise, including Warhol's signature bright red lips, made using lipstick, and a typically pop art blocked background, coloured with green and orange felt-tip pen".

BBC: Warhol sketch