diff --git a/exercise-009-rock/src/rock/game.go b/exercise-009-rock/src/rock/game.go
index d6a4e87..3034d9d 100644
--- a/exercise-009-rock/src/rock/game.go
+++ b/exercise-009-rock/src/rock/game.go
@@ -20,8 +20,8 @@ type Game struct {
 }
 
 // Add adds a player to the game
-func (g *Game) Add(p *Player) {
-	g.players = append(g.players, p)
+func (g *Game) Add(p Player) {
+	g.players = append(g.players, &p)
 	g.points = append(g.points, 0)
 }
 
@@ -43,8 +43,8 @@ func (g *Game) RoundRobin() {
 			b := g.players[j]
 
 			// Determine Winner
-			moveA := a.Play()
-			moveB := b.Play()
+			moveA := (*a).Play()
+			moveB := (*b).Play()
 			winner := Winner(moveA, moveB)
 
 			// Update Scores
@@ -63,6 +63,6 @@ func (g *Game) Display() {
 
 	// For Each Player
 	for i, p := range g.players {
-		fmt.Printf("%-15s %5d\n", p.Type(), g.points[i])
+		fmt.Printf("%-15s %5d\n", (*p).Type(), g.points[i])
 	}
 }
diff --git a/exercise-009-rock/src/rock/player.go b/exercise-009-rock/src/rock/player.go
index 6657f48..4a270ab 100644
--- a/exercise-009-rock/src/rock/player.go
+++ b/exercise-009-rock/src/rock/player.go
@@ -4,17 +4,83 @@ import (
 	"math/rand"
 )
 
-// Player ...
-type Player struct {
+// Player interface
+type Player interface {
+	Type() string
+	Play() int
 }
 
-// Type returns the type of the player
-func (p *Player) Type() string {
+// RandoRex player type
+type RandoRex struct {
+}
+
+// Type method for RandoRex
+func (p *RandoRex) Type() string {
 	return "RandoRex"
 }
 
-// Play returns a move
-func (p *Player) Play() int {
+// Play method for RandoRex
+func (p *RandoRex) Play() int {
 	choice := rand.Int() % 3
 	return choice
 }
+
+// Obsessed player type
+type Obsessed struct {
+	move int
+}
+
+// Type method for Obsessed
+func (p *Obsessed) Type() string {
+	return "Obsessed"
+}
+
+// Play method for Obsesses
+func (p *Obsessed) Play() int {
+	return p.move
+}
+
+// Flipper player type
+type Flipper struct {
+	move1 int
+	move2 int
+}
+
+// Type method for Flipper
+func (p *Flipper) Type() string {
+	return "Flipper"
+}
+
+// Play method for Flipper
+func (p *Flipper) Play() int {
+
+	// randomly select one of the two fixed moves
+	decision := rand.Int() % 2
+
+	var choice int
+	switch decision {
+	case 0:
+		choice = p.move1
+	case 1:
+		choice = p.move2
+	}
+	return choice
+}
+
+// Cyclone player type
+type Cyclone struct {
+	currentMove int // cycles through 0-2
+}
+
+// Type method for Cyclone
+func (p *Cyclone) Type() string {
+	return "Cyclone"
+}
+
+// Play method for Cyclone
+func (p *Cyclone) Play() int {
+	p.currentMove++
+	p.currentMove %= 3
+
+	return p.currentMove
+}
diff --git a/exercise-009-rock/src/rock/rock.go b/exercise-009-rock/src/rock/rock.go
index ff1ccfb..8dc93a0 100644
--- a/exercise-009-rock/src/rock/rock.go
+++ b/exercise-009-rock/src/rock/rock.go
@@ -6,9 +6,13 @@ func main() {
 	game := &Game{}
 
 	// Add Players
-	game.Add(&Player{})
-	game.Add(&Player{})
-	game.Add(&Player{})
+	game.Add(&RandoRex{})
+	game.Add(&RandoRex{})
+	game.Add(&RandoRex{})
+	game.Add(&Flipper{Rock, Paper})
+	game.Add(&Obsessed{Paper})
+	game.Add(&Obsessed{Scissors})
+	game.Add(&Cyclone{})
 
 	// A Thousand Round-Robins!
 	for i := 0; i < 1000; i++ {