April 17, 1820: Three hands out, all out.

NEW YORK CITY - It's easy to picture if you take a moment. A batter swings and drives a grounder toward the shortstop. As the shortstop bends down to get the ball the batter is running, head-down, toward first. The shortstop picks up the ball and, in one motion, fires it toward first. The first baseman stretches, one foot on the bag. The batter takes one last, long stride. You hear a "thud-thud." But which sound was the ball hitting the glove, and which one was the batter's foot hitting the base?It's another close play at first, made possible because of the distance of 90 feet from home plate to first base. It's the most perfectly measured distance in sports.

Some of baseball's most well-known rules are also the among the longest-standing rules in American sports. Three strikes and you're out, three outs and the inning is over, 90 feet between the bases, the ball must be hit between first and third base for it to be a fair ball, etc.

Many of baseball's well-known rules, and most of the ones still used today, were established by Alexander Cartwright, born April 17, 1820. Baseball was played in cities all across the country in the 1800s, often with different rules in each city. Cartwright recognized the need for a set of specific standards by which the game should be played so that teams from different areas could compete against each other without a lengthy discussion about the rules first.

By 1845, Cartwright's rules had started to become the norm across the country, and the continuity helped baseball spread from its northeastern roots. Many of his standardized rules have changed over the years - in Cartwright's rules, for example, the first team to 21 "counts," or runs, was the winner, regardless of how many "hands" (innings) had been played - but many more have stood the test of time. Rules like a batter being free to run to first if the catcher doesn't catch the third strike, three outs meaning the end of an inning, and a specific batting order have remained virtually unchanged for more than 150 years.

Cartwright is the closest thing the country has to a true Father of Baseball, though he wasn't universally recognized as such until after his death. It was his set of specific rules that allowed baseball to blossom into the game of strategy and intrigue it became.

The next time you're watching a baseball game, think about the close plays you see at first base. Think about how different the game would be if instead of 90 feet, the bases were set 88 feet apart, or 92. It's hard to say what inspired Cartwright to set the bases 90 feet apart, or make an inning last three outs, or establish any of the other rules he enforced. But they've been working for 150 years, and there's no sign of that ever changing.