some time ago i went to give a quote in an indian restaurant, never got the job and over the next 18 months they called me again for a quote. Upon the third time of going i said why don't i show you wat you get for your money? yes they said, so i got my machine and put a really briill X shaped figure in the middle of the carpet about 2 feet in diameter that stood out like a sore thumb.
Four months went by and still they hadn't had it cleaned then suddenly a phone call out of the blue... come and clean our restaurant. I put an extra £40 on the quotation )because of the extra dirt and grease that had now accumulated and went and did the job.
Apparently they had so many customers ask about the X shaped figure they eventually had it cleaned out of embarrasment. The restaurant has been a loyal customer since.
Dave