diff --git a/examples/basecoin/app/app.go b/examples/basecoin/app/app.go
index 1d31b0edc4..86860f0465 100644
--- a/examples/basecoin/app/app.go
+++ b/examples/basecoin/app/app.go
@@ -58,12 +58,12 @@ func NewBasecoinApp(logger log.Logger, db dbm.DB) *BasecoinApp {
 
 	// add handlers
 	coinKeeper := bank.NewCoinKeeper(app.accountMapper)
-	coolMapper := cool.NewMapper(app.capKeyMainStore)
+	coolKeeper := cool.NewKeeper(app.capKeyMainStore, coinKeeper)
 	ibcMapper := ibc.NewIBCMapper(app.cdc, app.capKeyIBCStore)
 	stakingMapper := staking.NewMapper(app.capKeyStakingStore)
 	app.Router().
 		AddRoute("bank", bank.NewHandler(coinKeeper)).
-		AddRoute("cool", cool.NewHandler(coinKeeper, coolMapper)).
+		AddRoute("cool", coolKeeper.Handler).
 		AddRoute("sketchy", sketchy.NewHandler()).
 		AddRoute("ibc", ibc.NewHandler(ibcMapper, coinKeeper)).
 		AddRoute("staking", staking.NewHandler(stakingMapper, coinKeeper))
diff --git a/examples/basecoin/app/app_test.go b/examples/basecoin/app/app_test.go
index f97ae30bf6..7168cb2161 100644
--- a/examples/basecoin/app/app_test.go
+++ b/examples/basecoin/app/app_test.go
@@ -259,12 +259,12 @@ func TestQuizMsg(t *testing.T) {
 	SignCheckDeliver(t, bapp, setTrendMsg1, 0, true)
 	SignCheckDeliver(t, bapp, quizMsg1, 1, true)
 	CheckBalance(t, bapp, "69icecold")
-	SignCheckDeliver(t, bapp, quizMsg2, 2, true) // result without reward
+	SignCheckDeliver(t, bapp, quizMsg2, 2, false) // result without reward
 	CheckBalance(t, bapp, "69icecold")
 	SignCheckDeliver(t, bapp, quizMsg1, 3, true)
 	CheckBalance(t, bapp, "138icecold")
 	SignCheckDeliver(t, bapp, setTrendMsg2, 4, true) // reset the trend
-	SignCheckDeliver(t, bapp, quizMsg1, 5, true)     // the same answer will nolonger do!
+	SignCheckDeliver(t, bapp, quizMsg1, 5, false)    // the same answer will nolonger do!
 	CheckBalance(t, bapp, "138icecold")
 	SignCheckDeliver(t, bapp, quizMsg2, 6, true) // earlier answer now relavent again
 	CheckBalance(t, bapp, "69badvibesonly,138icecold")
diff --git a/examples/basecoin/x/cool/errors.go b/examples/basecoin/x/cool/errors.go
new file mode 100644
index 0000000000..9001c3c243
--- /dev/null
+++ b/examples/basecoin/x/cool/errors.go
@@ -0,0 +1,15 @@
+package cool
+
+import (
+	sdk "github.com/cosmos/cosmos-sdk/types"
+)
+
+const (
+	// Cool module reserves error 300-399 lawl
+	CodeIncorrectCoolAnswer sdk.CodeType = 300
+)
+
+// ErrIncorrectCoolAnswer - Error returned upon an incorrect guess
+func ErrIncorrectCoolAnswer(answer string) sdk.Error {
+	return sdk.NewError(CodeIncorrectCoolAnswer, "Incorrect Cool answer - `"+answer+"'")
+}
diff --git a/examples/basecoin/x/cool/handler.go b/examples/basecoin/x/cool/handler.go
index c0aae11bba..fc3dc44ad4 100644
--- a/examples/basecoin/x/cool/handler.go
+++ b/examples/basecoin/x/cool/handler.go
@@ -5,7 +5,6 @@ import (
 	"reflect"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
-	"github.com/cosmos/cosmos-sdk/x/bank"
 )
 
 // This is just an example to demonstrate a functional custom module
@@ -19,37 +18,42 @@ import (
 // \_______/ \______/  \______/ |______/
 
 // Handle all "coolmodule" type objects
-func NewHandler(ck bank.CoinKeeper, cm Mapper) sdk.Handler {
-	return func(ctx sdk.Context, msg sdk.Msg) sdk.Result {
-		switch msg := msg.(type) {
-		case SetTrendMsg:
-			return handleSetTrendMsg(ctx, cm, msg)
-		case QuizMsg:
-			return handleQuizMsg(ctx, ck, cm, msg)
-		default:
-			errMsg := fmt.Sprintf("Unrecognized cool Msg type: %v", reflect.TypeOf(msg).Name())
-			return sdk.ErrUnknownRequest(errMsg).Result()
-		}
+func (k Keeper) Handler(ctx sdk.Context, msg sdk.Msg) sdk.Result {
+	switch msg := msg.(type) {
+	case SetTrendMsg:
+		return handleSetTrendMsg(ctx, k, msg)
+	case QuizMsg:
+		return handleQuizMsg(ctx, k, msg)
+	default:
+		errMsg := fmt.Sprintf("Unrecognized cool Msg type: %v", reflect.TypeOf(msg).Name())
+		return sdk.ErrUnknownRequest(errMsg).Result()
 	}
 }
 
 // Handle QuizMsg This is the engine of your module
-func handleSetTrendMsg(ctx sdk.Context, cm Mapper, msg SetTrendMsg) sdk.Result {
-	cm.SetTrend(ctx, msg.Cool)
+func handleSetTrendMsg(ctx sdk.Context, k Keeper, msg SetTrendMsg) sdk.Result {
+	k.setTrend(ctx, msg.Cool)
 	return sdk.Result{}
 }
 
 // Handle QuizMsg This is the engine of your module
-func handleQuizMsg(ctx sdk.Context, ck bank.CoinKeeper, cm Mapper, msg QuizMsg) sdk.Result {
+func handleQuizMsg(ctx sdk.Context, k Keeper, msg QuizMsg) sdk.Result {
 
-	currentTrend := cm.GetTrend(ctx)
+	correct := k.CheckTrend(ctx, msg.CoolAnswer)
 
-	if msg.CoolAnswer == currentTrend {
-		bonusCoins := sdk.Coins{{currentTrend, 69}}
-		_, err := ck.AddCoins(ctx, msg.Sender, bonusCoins)
-		if err != nil {
-			return err.Result()
-		}
+	if !correct {
+		return ErrIncorrectCoolAnswer(msg.CoolAnswer).Result()
+	}
+
+	if ctx.IsCheckTx() {
+		return sdk.Result{} // TODO
+	}
+
+	bonusCoins := sdk.Coins{{msg.CoolAnswer, 69}}
+
+	_, err := k.ck.AddCoins(ctx, msg.Sender, bonusCoins)
+	if err != nil {
+		return err.Result()
 	}
 
 	return sdk.Result{}
diff --git a/examples/basecoin/x/cool/keeper.go b/examples/basecoin/x/cool/keeper.go
new file mode 100644
index 0000000000..e1fbe8f587
--- /dev/null
+++ b/examples/basecoin/x/cool/keeper.go
@@ -0,0 +1,42 @@
+package cool
+
+import (
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/x/bank"
+)
+
+// Keeper - handlers sets/gets of custom variables for your module
+type Keeper struct {
+	ck bank.CoinKeeper
+
+	storeKey sdk.StoreKey // The (unexposed) key used to access the store from the Context.
+}
+
+// NewKeeper - Returns the Keeper
+func NewKeeper(key sdk.StoreKey, bankKeeper bank.CoinKeeper) Keeper {
+	return Keeper{bankKeeper, key}
+}
+
+// Key to knowing the trend on the streets!
+var trendKey = []byte("TrendKey")
+
+// GetTrend - returns the current cool trend
+func (k Keeper) GetTrend(ctx sdk.Context) string {
+	store := ctx.KVStore(k.storeKey)
+	bz := store.Get(trendKey)
+	return string(bz)
+}
+
+// Implements sdk.AccountMapper.
+func (k Keeper) setTrend(ctx sdk.Context, newTrend string) {
+	store := ctx.KVStore(k.storeKey)
+	store.Set(trendKey, []byte(newTrend))
+}
+
+// CheckTrend - Returns true or false based on whether guessedTrend is currently cool or not
+func (k Keeper) CheckTrend(ctx sdk.Context, guessedTrend string) bool {
+	if guessedTrend == k.GetTrend(ctx) {
+		return true
+	}
+	return false
+}
diff --git a/examples/basecoin/x/cool/mapper.go b/examples/basecoin/x/cool/mapper.go
deleted file mode 100644
index 2e0a791fa6..0000000000
--- a/examples/basecoin/x/cool/mapper.go
+++ /dev/null
@@ -1,30 +0,0 @@
-package cool
-
-import (
-	sdk "github.com/cosmos/cosmos-sdk/types"
-)
-
-// This Cool Mapper handlers sets/gets of custom variables for your module
-type Mapper struct {
-	key sdk.StoreKey // The (unexposed) key used to access the store from the Context.
-}
-
-func NewMapper(key sdk.StoreKey) Mapper {
-	return Mapper{key}
-}
-
-// Key to knowing the trend on the streets!
-var trendKey = []byte("TrendKey")
-
-// Implements sdk.AccountMapper.
-func (am Mapper) GetTrend(ctx sdk.Context) string {
-	store := ctx.KVStore(am.key)
-	bz := store.Get(trendKey)
-	return string(bz)
-}
-
-// Implements sdk.AccountMapper.
-func (am Mapper) SetTrend(ctx sdk.Context, newTrend string) {
-	store := ctx.KVStore(am.key)
-	store.Set(trendKey, []byte(newTrend))
-}
diff --git a/x/bank/mapper.go b/x/bank/keeper.go
similarity index 76%
rename from x/bank/mapper.go
rename to x/bank/keeper.go
index 0530967f12..919867c65d 100644
--- a/x/bank/mapper.go
+++ b/x/bank/keeper.go
@@ -6,6 +6,8 @@ import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 )
 
+const moduleName = "bank"
+
 // CoinKeeper manages transfers between accounts
 type CoinKeeper struct {
 	am sdk.AccountMapper
@@ -48,3 +50,18 @@ func (ck CoinKeeper) AddCoins(ctx sdk.Context, addr sdk.Address, amt sdk.Coins)
 	ck.am.SetAccount(ctx, acc)
 	return newCoins, nil
 }
+
+// SendCoins moves coins from one account to another
+func (ck CoinKeeper) SendCoins(ctx sdk.Context, fromAddr sdk.Address, toAddr sdk.Address, amt sdk.Coins) sdk.Error {
+	_, err := ck.SubtractCoins(ctx, fromAddr, amt)
+	if err != nil {
+		return err
+	}
+
+	_, err = ck.AddCoins(ctx, toAddr, amt)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}