Came out of this play feeling thankful that I could walk to Piccadilly without panic. The street-signs and lights were all in a harmless position, tucked into the bricks or resting on poles, and at least two foot away: a safe distance. A couple jostled past. A man’s hand hit mine. It hurt but it didn’t shake my inner being.

Thanks to ACIOTDITN, I am consciously grateful for my functioning limbic, parietal, and other regions that I can’t recall because I lack the total recall ‘malfunction’.  We, the audience, were let into what the majority are locked out of, given a brief peer into someone else’s box.  The box labelled ‘Asperger’, peculiar to us and particular to the 15 year old Christopher, is shown to contain a rare species of sense different from the common, that’s often more logical, and no less real. It’s perhaps closer to Nature than we give it or Nature credit for. Christopher sees everything that is and all that that entails; things and ways that we, in our own shared blindness, blank out in favour of a filtered self-created version that plays on repeat…

Those whose brains have a different mode for rendering reality can wake us up to the deception of perception. They show us we are walking through a carefully constructed creation of which we are largely the inventor. The film Inception, flawed though its concept may be on many levels, springs to mind. Since we all have access to the same ingredients and use the same tried and tested recipes, we have the delusion that there is only one way. This shared delusion dupes us into thinking that the cake on the table, with red jam and white cream and beige sponge is undoubtedly a cake on the table and has, in actual fact, those exact characteristics, in the real world, a world of real cake.

This play and book show us that there are other ways of constructing ‘reality’.

By leading us through Christopher’s labyrinthine mind, they make us think. They indicate the scale of the ‘inconvenient truth’ that most of us switch off. Christopher is permanently switched on. Like a wild animal not used to ‘civilised’ inertia, afraid to be touched, noticing everything, absorbing all the creation around him, he very quickly reaches saturation point. Electrified, he has a fit because he has trouble finding the off switch, feeling the universe’s constancy beam around him, all the time.

Obviously, this is highly inconvenient, at best, and crippling, even fatal, at worst. But there are lessons to be learned on both sides. Maths is the compass he uses for navigating through a world with the burden of total attention. Everyone knows that maths’ principle ingredient is truth. ‘Normal’ people can use maths to meet him in the middle. Maths can help ‘normals’ as it helps Christopher – help us navigate the shanty town we have built outside reality. Wherever our attention and perception stray, individually or collectively, maths will always lead us back.

After the ‘final’ curtain draw, the curtains re-open to reveal the answer  to our teenage hero’s  final maths A-Level exam question  – it’s about Pythagoras’ right-angled triangle and proving how and why it’s right-angled (or something.. – I’m as bad at maths as Christopher is at telling lies). The answer emerges like a celestial truth, drawn in chalk on the night sky of the stage back-drop. The equation was solved. It was true. I was somehow reassured and deeply moved.

Try as we like to draw ‘real’ lines through existence, between fantasy and reality, some things are fundamental, like maths, or faith.

The Curious Incident of the Dog in the Night-Time is based on Mark Haddon’s award-winning novel, adapted by Simon Stephens and directed by Marianne Elliott. The production won 7 Olivier Awards including Best Play in 2013 and is currently on tour in the UK.