Create a collection of icons representing [a theme], they be

Prompt

Create a collection of icons representing [a theme]; they belong together as a single theme. Put them in a 2x2 grid (no lines). The background is pure white. Make the icons look like risograph prints. No text. No color distortion. Vibrant and not faded. Use stochastic stippling and a sand-like noise pattern within color fills. Each icon has a thick black outline.