Tick is a fast, immediate-mode GUI library for building game UI in Unity entirely in code, no prefabs, canvases, or scene wiring. Widgets (buttons, sliders, textboxes, dropdowns, and more) are declared inline each frame, and Tick handles layout, state, and GPU-accelerated rendering. It's designed for in-game HUDs, menus, and debug tools, with built-in per-widget animation and pixel/percentage layout.