Not entirely happy with rock formation on right, but I have rock now
Look at Iwagumi-style tanks, but without the plants.
From Wikipedia:
The Iwagumi style is a specific subtype of the nature style. The
Iwagumi term itself comes from the Japanese "rock formation" and refers to a layout where stones play a leading role. In the
Iwagumi style, each stone has a name and a specific role. Rocks provide the bony structure of the aquascape and the typical geometry employs a design with three main stones, with one larger stone and two other smaller stones, although additional rocks can also be used. The
Oyaishi, or main stone, is placed slightly off-center in the tank, and
Soeishi, or accompanying stones, are grouped near it, while
Fukuseki, or secondary stones, are arranged in subordinate positions. The location of the focal point of the display, determined largely by the asymmetric placement of the
Oyaishi, is considered important, and follows ratios that reflect Pythagorean tuning.
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