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This is the first part of three episodes to demonstrate a renewal approachfor proving the Four Color Theorem without checking by a computer. The secondand the third episodes have subtitles: ``R/G/B Kempe chains in an extremumnon-4-colorable MPG'' and ``Diamond routes, canal lines and$\Sigma$-adjustments,'' where R/G/B stand for red, green and blue colors topaint on edges and an MPG stands for a maximal planar graph. In this firstpart, we introduce R/G/B-tilings as well as their tri-coexisting versionRGB-tiling on an MPG or a semi-MPG. We associate these four kinds ofedge-colorings with 4-colorings by 1/2/3/4 on vertices in MPS's or semi-MPG's.Several basic properties for tilings on MPG's and semi-MPG's are developed.Especially the idea of R/G/B-canal lines, as well as canal system, is acornerstone. This work started on May 31, 2018 and was first announced by theauthor~\cite{Liu2020} at the Institute of Mathematics, Academia Sinica, Taipei,Taiwan, on Jan.\ 22, 2020, when the pandemic just occurred.

A renewal approach to prove the Four Color Theorem unplugged, Part I: RGB-tilings on maximal planar graphs