This repository is a reference Yocto/OpenEmbedded layer collection demonstrating the KISS (Keep It Simple, Stupid) principle for embedded Linux build systems. It provides a minimal but realistic setup for building bootable images for four fictitious products based on real development boards: BeagleBone Black (dogbonedark), STM32MP157A-DK1 (stompduck), NXP FRDM i.MX93 (freiheit93), and AMD ZynqMP Kria KD240 (krazymp). The architecture consists of a base distro layer (meta-kiss) with common recipes and machine-specific layers (meta-kiss-ti, meta-kiss-st, meta-kiss-nxp, meta-kiss-amd) that add board-specific configurations, bootloaders, kernel defconfigs, and firmware handling. The build process is orchestrated via kas configuration files or bitbake-setup, automatically fetching all required upstream layers (bitbake, openembedded-core, meta-arm, meta-openembedded, meta-xilinx). The repository serves as a teaching tool and starting point for companies wanting to create clean, maintainable Yocto setups without unnecessary complexity. It is not a standalone application but a build system configuration; its value lies in the patterns and practices it demonstrates rather than reusable code components.