The bat's form has become more refined over time. In the mid-19th century, baseball batters were known to shape or whittle their own bats by hand. This allowed there to be a wide variety in shape, size, and weight. For example, there were flat bats, round bats, short bats, and fat bats. Earlier bats were known to be much heavier and larger than today's regulated ones. During the 19th century, many shapes were experimented with, as well as handle designs. Today, bats are much more uniform in design.
There are limitations to how much and where a baseball player may apply pine tar to a baseball bat. According to Rule 1.10(c) of the Major League Baseball Rulebook, it is not allowed more than 18 inches up from the bottom handle. An infamous example of the rule in execution is the Pine Tar Incident on July 24, 1983. Rules 1.10 and 6.06 were later changed to reflect the intent of Major League Baseball, as exemplified by the league president's ruling. Rule 1.10 now only requires that the bat be removed from the game if discovered after being used in a game; it no longer necessitates any change to the results of any play which may have taken place. Rule 6.06 refers only to bats that are "altered or tampered with in such a way to improve the distance factor or cause an unusual reaction on the baseball. This includes, bats that are filled, flat-surfaced, nailed, hollowed, grooved or covered with a substance such as paraffin, wax, etc." It no longer makes any mention of an "illegally batted ball". In 2001, MLB approved the use of Gorilla Gold Grip Enhancer in major and minor league games as an alternative to pine tar.
Players can also create complex holes such as ‘two-part holes’ where the players must hit or reach one object before attempting to shoot at the hole. For example, a ‘two-part hole’ could consist of hitting the scoreboard first, and then once they have hit the scoreboard they must hit the ball back to home plate, that would be one hole with the player with the fewest strokes winning the hole. ‘Two-part holes’ are typically saved for the last hole in order to make things more complex and difficult on the leader.