Sentence:  <WSD>At</WSD> the same time , the wallpaper strips themselves seem to be pushed into depth by the lines and patches of shading charcoaled upon them , and by their placing in relation to the block capitals ; and these capitals seem in turn to be pushed back by their placing , and by contrast with the corporeality of the woodgraining . 
Meaning of the word marked with <WSD> tags:  at the same instant