If we go off the plane (making the question a bit wider) we can use tubes (actually it is even possible to make 3D tube fonts).
Here is the simplest example with letter “P” - https://www.babylonjs-playground.com/#165IV6#914
And with small offset of the clone - https://www.babylonjs-playground.com/#165IV6#917
Then we can add some plane where the neon signs are usually somehow mounted; then merge, clone, position and merge again - to have just 1 mesh at the end - https://www.babylonjs-playground.com/#165IV6#919 (and dispose materials which we don’t need anymore).
And finally we may add some simple effects https://www.babylonjs-playground.com/#165IV6#921
It is possible even to imitate vintage dribble, like in this CSS example
https://codepen.io/eldinor/pen/vYBbJeW