Trade is the name given by game author Kate Jones to cooperative variants of two of her geometry games, Marshall Squares and Rhominoes. Here are the full rules for both variants, as given to me by Kate Jones:

Example of a finished game of Marshall Squares (not the Trade variant). 
Trade (2 to 5 players) [Marshall Squares variant]
Divide the tiles among the players as follows, and state the respective
goal:
. 2 players  2 solid tiles each plus 10 randomly chosen tiles (omit the
fifth solid tile)
 goal: 3x4 rectangle
. 3 players  1 solid tile each plus 7 randomly chosen tiles (omit one
solid tile)
 goal: 2x4 rectangle
. 4 players  1 solid tile each plus 5 randomly chosen tiles (omit one
solid tile)
 goal: 2x3 rectangle
. 5 players  1 solid tile each plus 4 randomly chosen tiles
 goal: P pentomino
As soon as all the tiles are dealt out, on a signal the players try to form
their hand of tiles into the shape indicated, joining tiles by color. If a
color is needed or a tile won't fit, a player may offer to trade with
another player for a tile they need, in exchange for one the other player
may need.
The first player to complete the figure wins 5 points. Second player to
finish wins 4 points, and so on. However, points are not awarded until all
players have succeeded. This is also a fine game for teambuilding and
management training seminars. It is also one of our paradigms for
nonpredatory games.

Example of a finished game of Rhomino (not the Trade variant). 
Trade (2 to 5 players) [Rhominoes variant]
Randomly deal out all the tiles: 12, 8, 6, 5 tiles respectively for 2, 3,
4, 5 players. If a tile remains, set it aside as a spare. On a signal,
players begin to assemble their tiles into an agreedupon shape, matching
colors throughout. For 5 players, use any of the pentadiamonds on page 5 or
pentarhombs on page 7. This wavy shape is best to start with:
For 4 players, choose one of these as the goal shape: [figures missing]
(Use the triangle for more advanced challenges.)
For 3 players, choose one of these: [figures missing]
For 2 players, build any symmetrical figure.
The first player to complete the shape earns 5 points; the second 4, then 3,
2 and 1, depending on the number of players. Players who need certain colors
may offer to trade with any other player so both get what they need. Any
player may exchange a tile with the spare tile, if any, as often as needed.
Players get 1 bonus point for each trade with another player, but no points
for the spare. For 2 players, give each player a bonus point for the number
of contact edges in their figure. Largest point total wins.
The winner is determined only after all players have succeeded. This is a
fine game for teambuilding and management training seminars. It is also one
of our paradigms for nonpredatory games.
If you are the maker of this game, or if you have played it and want to submit a review, please email me.