Following the Warsaw Pact invasion of Czechoslovakia in 1968, Pištěk's drawings resembled targets with bullet holes, and their composition was accented by the use of monochromatic blocks of colour ("August Picture I–III", 1968–1969). His series of drawings in ink and nitrocellulose lacquer continued until the beginning of the 1970s ("View Inside", 1970; "Half-Life", 1970) and was followed by coloured compositions of geometrical forms ("Reflection", 1971) and small-format oil paintings in which the geometrical order of blocks of colour was broken by small irregularities ("Fall", 1973; "House", 1973). He returned to monochrome paintings in ink and nitrocellulose lacquer in the early 1980s in compositions of artificial architecture ("Where I Will Live Next", 1982), which later became three-dimensional labyrinths ("City", 1997).