While crossing the US-Mexican border on his bicycle, the man was stopped by a guard who pointed to two sacks the man had on his shoulders. "What's in the bags?", asked the guard.
"Sand," said the cyclist.
"Get them off - we'll take a look," said the guard.
The Cyclist did as he was told, emptied the bags, and proving they contained nothing but sand, reloaded the bags, put them on his shoulders and continued across the border.
Two weeks later, the same thing happened. Again the guard demanded to see the two bags, which again contained nothing but sand. This went on every week for six months, until one day the cyclist with the sand bags failed to appear.
A few days later, the guard happened to meet the cyclist downtown. "Say friend, you sure had us crazy", said the guard. "We knew you were smuggling something across the border. I won't say a word - but what is it you were smuggling?" "Bicycles!"
Juan comes up to the Mexican border on his bicycle. He's got two large bags over his shoulders. The guard stops him and says, "What's in the bags?"
"Sand," answered Juan.
The guard says, "We'll just see about that, get off the bike." The guard takes the bags and rips them apart; he empties them out and finds nothing in them but sand.
He detains Juan overnight and has the sand analyzed, only to discover that there is nothing but pure sand in the bags.
The guard releases Juan, puts the sand into new bags, hefts them onto the man''s shoulders, and lets him cross the border.
A week later, the same thing happens. The guard asks, "What have you got?"
"Sand," says Juan.
The guard does his thorough examination and discovers that the bags contain nothing but sand.He gives the sand back to Juan, and Juan crosses the border on his bicycle.
This sequence of events if repeated every day for three years. Finally, Juan doesn't show up one day and the guard meets him in a Cantina in Mexico.
"Hey, Buddy," says the guard, "I know you are smuggling something. It's driving me crazy. It's all I think about. I can't sleep. Just between you and me, what are you smuggling?"
Juan sips his вееr and says, "Bicycles."