2 years later: March 2007.
The inner wall of the tunnel had been repainted. We do not know who did it, probably the ward, city or prefecture office.
The lower half of the wall on the right is now neatly repainted.
A closer look shows that the yellow tape is still there.
The people who worked on it probably thought it was an official traffic sign. We can see how effort was made to keep it as it was.
Without my knowledge, my extremely personal act is gradually becoming an accepted landscape and is about to be integrated into the town.
More than 80% of the tape remains on utility poles, guardrails and other spots - still glittering.