ClockUp

Background
ClockUp is a Japanese visual novel and eroge developer founded in 2002. The company is mostly known for their dark, transgressive eroge novels like Euphoria and Maggot Baits although they also produce more standard titles.

Logo (2000s-)
Visuals: We see a semi-quartered circle with the divided part in pink and "CLOCKUP" mostly in black with the "K" in the same pink color.

Variants:
 * On Euphoria, the text is just hand-written on paper.
 * On Maggot Baits, a dimmed, abstract pink background is shown behind the small logo.

Technique: None.

Audio: None, or a voice saying "ClockUp". Availability: Seen on most of their titles from 2000s onwards.