“Oh!” I said, rather disappointed. “And then?”
Poirot’s eyes twinkled a little.
“And then I say to myself, ‘Since there is here something that I do not understand, it would be well that I should investigate the matter. I must not permit myself to be wholly engrossed by the Big Four.’ Ah! we are just arriving. My little clothes brush, where does it hide itself? Here it is—brush me down, I pray you, my friend, and then I will perform the same service for you.”
“Yes,” said Poirot thoughtfully, as he put away the brush, “one must not permit oneself to be obsessed by one idea. I have been in danger of that. Figure to yourself, my friend, that even here, in this case, I am in danger of it. Those two lines you mentioned, a downstroke and a line at right angles to it, what are they but the beginning of a 4?”
“Good gracious, Poirot,” I cried, laughing.
“Is it not absurd? I see the hand of the Big Four everywhere, it is well to employ one’s wits in a totally different milieu. Ah! There is Japp come to meet us.”