Union
$$A \cup B =$$
{ belly, ears, eyes, feet, forming, hands, head, mouth, norming, performing, storming, thighs }
Symmetric Difference
$$A \ominus B =$$
{ belly, ears, eyes, feet, forming, hands, head, mouth, norming, performing, storming, thighs }
Cartesian Product
$$A \times B =$$
{ (forming, belly),
(forming, ears),
(forming, eyes),
(forming, feet),
(forming, hands),
(forming, head),
(forming, mouth),
(forming, thighs),
(norming, belly),
(norming, ears),
(norming, eyes),
(norming, feet),
(norming, hands),
(norming, head),
(norming, mouth),
(norming, thighs),
(performing, belly),
(performing, ears),
(performing, eyes),
(performing, feet),
(performing, hands),
(performing, head),
(performing, mouth),
(performing, thighs),
(storming, belly),
(storming, ears),
(storming, eyes),
(storming, feet),
(storming, hands),
(storming, head),
(storming, mouth),
(storming, thighs) }
Tuckman's stages of group development