Pahoehoe lava is smooth and ropy while Aa lava is blocky and hard. Initial symptoms include large, angular or blocky, yellow areas visible on the upper surface. He thought the models were "blocky" and their textures "murky" or "blurry". They are upward-fining, lenticular to sheet-like bodies that are yellowish, steep-faced and blocky in outcrop. The images created with ray-tracing programs have noticeable blocky shapes on the terrain. Pseudomorphs after more tabular or blocky azurite crystals also occur. The Stack has a "blocky, black, and rectangular" look with the ThinkPad logo. Blocky and equant clasts with low vesicle content are formed. The margins of the white markings are crisp, smooth, blocky, and well-defined. Typical orthosilicates tend to form blocky equant crystals, and are fairly hard. Weiss described the graphics as blocky and insipid, the sound as repetitive and derivative. In blocky structure, the structural units are blocklike or polyhedral. The blocky lava flows still maintain their original forms. The volcano is high and features both blocky lava flows and scoria flows. Blocky andesite lava then flowed from St. Helens' summit crater down the volcano's southeast flank.