End zone

Unlike sports like association football and ice hockey which require the ball/puck to pass completely over the goal line to count as a score, both Canadian and American football merely need any part of the ball to break the vertical plane of the outer edge of the goal line.

The end zones were invented as a result of the legalization of the forward pass in gridiron football.

However, the rules governing the scoring of singles were changed: teams were required to either kick the ball out of bounds through the end zone or force the opposition to down a kicked ball in their own end zone in order to be awarded a point.

In Canadian football stadiums that also feature a running track, it is usually necessary to truncate the back corners of the end zones, since a rectangular field 150 yards long and 65 yards wide will not fit completely inside an oval-shaped running track.

Such truncations are marked as straight diagonal lines, resulting in an end zone with six corners and six pylons.

Nowadays, for player safety reasons, almost all goal posts in the professional and collegiate levels of American football are T-shaped (resembling a slingshot), and reside just outside the rear of both end zones; such goalposts, first seen in 1966, were invented by Jim Trimble and Joel Rottman in Montreal, Quebec, Canada.

[citation needed] At the high school level, it is not uncommon to see multi-purpose goal posts that include football goal posts at the top and a soccer net at the bottom; these are usually seen at smaller schools and in multi-purpose stadiums where facilities are used for multiple sports.

Many championship and bowl games at college and professional level are commemorated by the names of the opposing teams each being painted in one of the opposite end zones.

In the CFL, fully painted end zones are nonexistent, though some feature club logos or sponsors.

In many places, particularly in smaller high schools and colleges, end zones are undecorated, or have plain white diagonal stripes spaced several yards apart, in lieu of colors and decorations.

[8] In professional football, since 2004, the Pittsburgh Steelers of the NFL have the south end zone at Acrisure Stadium (formerly Heinz Field) painted with diagonal-lines during most of the regular season, with the north end zone featuring only the city name of Pittsburgh in yellow.

This is done because Acrisure Stadium, which has a natural grass playing surface, is also home to the Pittsburgh Panthers of college football and the markings simplify field conversion between the two teams' respective field markings and logos, with both teams sharing a secondary yellow color, but each having different primary colors.

[9] Likewise, some end zones are painted in tribute to a recently deceased team figure or fan, as is done with the Steelers' AFC North rival Baltimore Ravens at M&T Bank Stadium, where the city name is painted as usual in the end zone, except for the "MO" portion, which is painted in gold, white or black in tribute to the late Mo Gaba, a young fan of both the Ravens and Orioles.