I have vivid recollections of trying to take physical exercise in a playground like a mountain, rising one in 10, with a knobbly surface.
More fluid basaltic lava flows tend to form flat sheet-like bodies, whereas viscous rhyolite lava flows forms knobbly, blocky masses of rock.
The field was knobbly, and the airplane bounced and turned a somersault.
The knobbly surface reflects sound waves that come through the spermaceti organ from the phonic lips.
The holdfast is a large, hollow, knobbly structure.
The margin is blunt, smooth at first but later becomes serrated and knobbly.
The fruiting bodies are white, knobbly and relatively hard, requiring a fair amount of force to break.
The bark is smooth and pale grey on young trees, becoming square-cracked and knobbly on old trees.
