Complex sentence: Littleton wrote that during the time Eisch worked in his studio, his influence on Littleton was so strong that for weeks after Eisch returned to Germany, Littleton found himself creating works that were derivative of his friend's complex, intuitively-shaped forms.
Split into simpler sentences: Littleton wrote that during the time Eisch worked in his studio, his influence on Littleton was strong. For weeks after Eisch's return to Germany, Littleton found himself creating works that were derivative of his friend's complex, intuitively-shaped forms.