The CTEC logo is adopted from Classic Tetris European Championship – CTWC to make a shared experience for players, followers & organisers. It is designed by Vince Clemente and is the second version. The first version, the T-version (link), was cancelled in order to respect the Tetris trademark.
CTEC writes CTEC where CTWC writes CTWC.
The “reversed” edition was introduced back in 2019 by Chrisstoffer and during the planing of CTEC 2021 Online the organisers agreed to make this the official version from 2021 and onwards.
The “reversed” logo is the same as the logo used for CTWC but the top rows of blocks are mirrored. It is done to symbolise that CTEC (PAL) is the same as CTWC (NTSC) – yet different.