Defensive play - Under front

"In American football, a 4–3 defense is a defensive alignment consisting of four down linemen and three linebackers. It is probably the most commonly used defense in modern American football and especially in the National Football League. ...
In the original version of the 4–3, the tackles lined up over the offensive guards and the ends lined up on the outside shoulder of the offensive tackles, with the middle linebacker over the center and the other linebackers outside the ends. In the mid-1960s Hank Stram developed a popular variation, the "Kansas City Stack", which shifted the strong side defensive end over the tight end, stacked the strongside linebacker over the tackle, and shifted the weakside tackle over center. At about the same time the Cleveland Browns frequently used a weakside shift. The Dallas Cowboys coach Tom Landry developed a "flex" variation, in order to take advantage of the quickness of his Hall of Fame tackle, Bob Lilly. In Tom Landry's original 4–3 defenses (4-3 Inside and 4-3 Outside), both defensive tackle were flexed. In the "flex", on a pro set right, with defensive keys showing a run to the right, the right defensive tackle would be flush on the line and was supposed to penetrate. The right defensive end and left defensive tackle were flexed two feet off the line of scrimmage, the right defensive end now head on with the left offensive tackle (i.e. a 4-2-2-5 front instead of the more common 5-2-2-5 front). This gave the defense a "zig zag" look unlike any other of its day. More modern versions of the 4-3 include the Tampa 2 scheme and the 4-3 slide." [4–3 defense. Wikipedia]
The American football positions diagram example "Defensive play - Under front" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Football solution from the Sport area of ConceptDraw Solution Park.

"The goal line is the chalked or painted line dividing the end zone from the field of play in American football and Canadian football. It is the line that must be crossed in order to score a touchdown
If any part of the ball reaches any part of the imaginary vertical plane transected by this line while in-bounds and in possession of a player whose team is striving toward that end of the field, this is considered a touchdown and scores six points for the team whose player has advanced the ball to, or recovered the ball in, this position. This is in contrast with other sports like Association football and ice hockey, which require the puck or ball to pass completely over the goal line to count as a score.
If any member of the offensive team is downed while in possession of the ball behind his own team's goal line, this is called a safety and scores two points for the defensive team.
If, during the course of play, a loose ball travels past the goal line and is recovered within the end zone, then it is a touchdown if recovered by the kicking team, or a touchback if recovered and downed by the receiving team.
In the event of a kick recovered in one's own end zone, the entirety of the ball must pass the goal line in order for the ball to be considered in the field of play, and not a touchback." [Goal line (gridiron football). Wikipedia]
The American football positions diagram example "Goal line formation (Offense/ Defense)" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Football solution from the Sport area of ConceptDraw Solution Park.

"In association football, the formation describes how the players in a team are positioned on the pitch. Different formations can be used depending on whether a team wishes to play more attacking or defensive football. ...
The 4–3–3 was a development of the 4–2–4, and was played by the Brazilian national team in the 1962 World Cup. The extra player in midfield allows a stronger defence, and the midfield could be staggered for different effects. The three midfielders normally play closely together to protect the defence, and move laterally across the field as a coordinated unit. The three forwards split across the field to spread the attack, and may be expected to mark the opposition full-backs as opposed to doubling back to assist their own full-backs, as do the wide midfielders in a 4–4–2. When used from the start of a game, this formation is widely regarded as encouraging expansive play, and should not be confused with the practice of modifying a 4–4–2 by bringing on an extra forward to replace a midfield player when behind in the latter stages of a game. This formation is suited for a short passing game and useful for ball retention.
A staggered 4–3–3 involving a defensive midfielder (usually numbered four or six) and two attacking midfielders (numbered eight and ten) was commonplace in Italy, Argentina, and Uruguay during the 1960s and 1970s. The Italian variety of 4–3–3 was simply a modification of WM, by converting one of the two wing-halves to a libero (sweeper), whereas the Argentine and Uruguayan formations were derived from 2–3–5 and retained the notional attacking centre-half. The national team which made this famous was the Dutch team of the 1974 and 1978 World Cups, even though the team won neither." [Formation (association football). Wikipedia]
The diagram example "Association football (soccer) formation 4-3-3" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Football solution from the Sport area of ConceptDraw Solution Park.
www.conceptdraw.com/ solution-park/ sport-soccer

"In association football, the formation describes how the players in a team are positioned on the pitch. Different formations can be used depending on whether a team wishes to play more attacking or defensive football. ...
The WM system was created in the mid-1920s by Herbert Chapman of Arsenal to counter a change in the offside law in 1925. The change had reduced the number of opposition players that attackers needed between themselves and the goal-line from three to two. This led to the introduction of a centre-back to stop the opposing centre-forward, and tried to balance defensive and offensive playing. The formation became so successful that by the late-1930s most English clubs had adopted the WM. Retrospectively, the WM has either been described as a 3–2–5 or as a 3–4–3, or more precisely a 3–2–2–3 reflecting the letters which symbolised it. The gap in the centre of the formation between the two wing halves and the two inside forwards allowed Arsenal to counter-attack effectively. The W-M was subsequently adapted by several English sides, but none could apply it in quite the same way Chapman had. This was mainly due to the comparative rarity of Alex James in the English game. He was one of the earliest playmakers in the history of the game, and the hub around which Chapman's Arsenal revolved." [Formation (association football). Wikipedia]
The diagram example "Association football (soccer) formation 3-2-5 (WM)" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Football solution from the Sport area of ConceptDraw Solution Park.
www.conceptdraw.com/ solution-park/ sport-soccer

"In American football, each team has eleven players on the field at one time. The specific role that a player takes on the field is called their position. Under the modern rules of American football, teams are allowed unlimited substitutions, that is teams may change any number of players after any play. This has resulted in the development of three "platoons" of players, the offense (the team with the ball, who is trying to score), the defense (the team trying to prevent the other team from scoring, and to take the ball from them), and the special teams (who play in kicking situations). Within those platoons, various specific positions exist depending on what the player's main job is." [American football positions. Wikipedia]
The American football positions diagram example "3-4 Defense" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Football solution from the Sport area of ConceptDraw Solution Park.