LAS VEGAS (AP) Dr. James Naismith created the original 13 rules for basket ball in 1892, outlining the method of scoring, what constitutes a foul and how to determine which team wins.
Those rules evolved as the game grew.
The peach baskets were replaced by rims and backboards were added. Team sizes were trimmed from nine to five players, the name of the game became one word. Players were allowed to dribble the ball, scoring increased from one to two points for a made basket.
Other rules were added later: A midcourt line to prevent stalling, a 3-second area to keep offensive players from camping around the basket, goaltending to stop tall players from swatting nearly every shot away from the basket.
But as basketball expanded into multiple levels, the rules spider webbed into varying directions.
International basketball developed different rules than the NBA. College basketball had its own tweaks, even from men's to women's. High school and youth basketball created their own sets of rules to suit players in those age groups.
Everyone is playing the same basic game, but not always under the same regulations.
''FIBA, the NBA, college and high school, I wish we all had the same rules,'' said Nevada coach Eric Musselman, who spent nine years as an NBA coach. ''To me, it's too confusing for the average fan to watch an NBA when there's a 24-second clock in the NBA, then you watch the NCAA and there's a different clock. Or you watch a women's game and there's four quarters and the men's game has two halves. We've got to make it simple for the fan.''
It can be confusing. Depending on what level the game is being played, the 3-point line, the shot clock, even the rim and court sizes could all be different.
FIBA plays four 10-minute quarters while the NBA has four 12-minute quarters. Men's college basketball has two 20-minute halves, but the women play four 10-minute quarters. The WNBA used to have 20-minute halves, but now has 10-minute quarters. High school games have four 8-minute quarters.
Shot clock, same thing. FIBA, the NBA and WNBA all have a 24-second shot clock. NCAA men and women have a 30-second shot clock, though the men were 35 seconds before the 2015-16 season. In high school basketball, some states have a shot clock, others don't.
Even timeouts are widely varied; type, duration, number allowed, who can call one.
''I can't understand why we can't have world rules,'' New Mexico coach Craig Neal said. ''Everybody plays by the same line, everybody plays by the same shot clock, the same ball. To me, that's kind of confusing.''
Distances can vary, too.
FIBA has a trapezoid lane that widens from 12 to 19 feet. The NBA and WNBA lane is 16 feet straight across, but the NCAA lane is 12 feet, same as high schools.
The NBA has the deepest 3-point line at 23 feet, 9 inches. FIBA's line is 20-6, just like the WNBA, and the NCAA line is 19-9, just like high schools.
In North American sports, changes are often made in ball sizes, court/field dimensions, goal sizes. Depending on the age group, the basketball rim can be 10, 9 or 8 feet high.
''We make more modifications for the sports than any other country,'' Wake Forest coach Danny Manning said. ''I just think we've got to get to a point where the rules are the rules. Internationally, you have the FIBA rules. Those are the rules.''
The key is finding a set of rules that will work everyone. That won't be easy.
For one, the games are different.
Basketball, as much as any other sport, has a massive gap in talent from one level to the next. NBA players are bigger, stronger, faster, play more above the rim and can shoot from farther out than anyone else, even on the international level. For them to have the same rules as, say, a 12-and-under rec league team may not make that much sense.
''I think there needs to be a combination of international play in the NBA and college rules,'' Michigan State coach Tom Izzo said. ''I don't think you definitely go to NBA rules. I don't feel that way because it's a different game, a different caliber of athlete.''
There's also an issue of getting FIBA, the NBA, NCAA and National Federation of High School Associations to collaborate. That may be next to impossible.
''Everybody's going to make their own decision,'' ACC Commissioner John Swofford said. ''The NBA's going to do what the NBA wants to do, the Olympic committee is going to do what they want to do. But I think it's worth considering.''
AP Sports Writer Dave Skretta in Kansas City, Missouri, contributed to this story. For more AP college basketball: http://collegebasketball.ap.org