What compound was drawn on this sidewalk?

Question

A friend found this in the sidewalk of Kent town of Canterbury:

What compound is this, and why would its picture be there?

Answer 1

Certainly, it's meant to be trinitrotoluene, TNT, with a "typo". Perhaps a craftsman tried to copy an image, such as that from Wikipedia, below, which shows the oxygen atoms outside the ring:

As to the reason for that sidewalk plaque:

Faversham, ~16 km from Canterbury, produced TNT, and on April 2, 1916, some 200 tons of TNT exploded, killing 115 people (apparently set off by other munitions -- it is rather difficult to detonate TNT alone). "News of the blast was kept secret due to the wartime sensitivities at the time. It is now recognised as the worst ever disaster in the UK explosives industry."

While there's a monument at the mass burial in Faversham, below, the plaque might be an additional memorial.

This is reminiscent of the Halifax, NS, CA munitions explosion, December 6 1917. with "equivalent energy of roughly 2.9 kilotons of TNT", killing about 2,000.

However, it might also be a crafty advertisement, if in somewhat poor taste, for either:

• TNT Improv and Sketch Comedy Society in Canterbury at University of Kent
• TNT Delivery

Answer 2

The inner of the structure formula neither is a character, nor a number. It is a Thiele ring (suggested by Johannes Thiele 1865-1918 by 1899) to describe aromaticity, after Kekulé's approach already was disseminated. It was an old practice (say up to about 1960s) you still may encounter in the electronic age, e.g.

when you neither want to draw one structure instead of the resonance structure on the very left, and the one on the very right, or because your sketcher program (ChemDraw, Chemdoodle, etc.) falls in this form. Or, because you encounter such a drawing you want to assign a (kekulized) SMILES string:

(credit to both drawings: Noel O'Boyle, John W. Mayfield. We need to talk about... Kekulization, Aromaticity, and SMILES. 254th ACS National Meeting Washington, August 2017. Archived on Noel O'Blog).

However, because it represents recurrent potential pitfall when counting how many electrons actually are present, especially if chemists from different experience/with different convention in their mind meet each other:

(Robert Grossmann The Art of Writing Reasonable Organic Reaction Mechanisms., already used earlier here)

especially in charged states (e.g., the assumed intermediate anions of Birch reductions), the safer (hence better) approach is to use mesomeric resonance formulae instead (and to recall that benzene isn't 1,3,6-cyclohexatriene with an alternating pattern of single and double bonds).