Present participle; Past participle - gridironing - gridironed Present - gridiron - gridiron - gridirons - gridiron - gridiron - gridiron Past - gridironed - gridironed - gridironed - gridironed - gridironed - gridironed Future - will gridiron - will gridiron - will gridiron - will gridiron - will gridiron - will gridiron Present conditional - would gridiron - would gridiron - would gridiron - would gridiron - would gridiron - would gridiron Present Perfect - have gridironed - have gridironed - has gridironed - have gridironed - have gridironed - have gridironed Past Perfect - had gridironed - had gridironed - had gridironed - had gridironed - had gridironed - had gridironed Future Perfect - will have gridironed - will have gridironed - will have gridironed - will have gridironed - will have gridironed - will have gridironed Past conditional - would have gridironed - would have gridironed - would have gridironed - would have gridironed - would have gridironed - would have gridironed Imperative - - - gridiron - - - - - - - -