diff --git a/example/blocks.go b/example/blocks.go
index d22bbad28..ddc7d0f6e 100644
--- a/example/blocks.go
+++ b/example/blocks.go
@@ -18,9 +18,8 @@ package main
 
 import (
 	"flag"
-	"github.com/hajimehoshi/ebiten"
 	"github.com/hajimehoshi/ebiten/example/blocks"
-	"github.com/hajimehoshi/ebiten/glfw"
+	"github.com/hajimehoshi/ebiten/runner"
 	"log"
 	"os"
 	"runtime"
@@ -44,9 +43,8 @@ func main() {
 		defer pprof.StopCPUProfile()
 	}
 
-	ui := new(glfw.UI)
 	game := blocks.NewGame()
-	if err := ebiten.Run(ui, game, blocks.ScreenWidth, blocks.ScreenHeight, 2, "Blocks (Ebiten Demo)", 60); err != nil {
+	if err := runner.Run(game, blocks.ScreenWidth, blocks.ScreenHeight, 2, "Blocks (Ebiten Demo)", 60); err != nil {
 		log.Fatal(err)
 	}
 }
diff --git a/glfw/canvas.go b/internal/glfw/canvas.go
similarity index 96%
rename from glfw/canvas.go
rename to internal/glfw/canvas.go
index 73a12640c..a009d7111 100644
--- a/glfw/canvas.go
+++ b/internal/glfw/canvas.go
@@ -32,7 +32,7 @@ type canvas struct {
 	funcsDone chan struct{}
 }
 
-func (c *canvas) draw(d ebiten.GraphicsContextDrawer) (err error) {
+func (c *canvas) draw(d GraphicsContextDrawer) (err error) {
 	c.use(func() {
 		c.context.PreUpdate()
 	})
diff --git a/glfw/context.go b/internal/glfw/context.go
similarity index 100%
rename from glfw/context.go
rename to internal/glfw/context.go
diff --git a/glfw/input.go b/internal/glfw/input.go
similarity index 100%
rename from glfw/input.go
rename to internal/glfw/input.go
diff --git a/glfw/ui.go b/internal/glfw/ui.go
similarity index 93%
rename from glfw/ui.go
rename to internal/glfw/ui.go
index 9ac8f9a73..593670a6c 100644
--- a/glfw/ui.go
+++ b/internal/glfw/ui.go
@@ -30,6 +30,10 @@ func init() {
 	})
 }
 
+type GraphicsContextDrawer interface {
+	Draw(d ebiten.GraphicsContext) error
+}
+
 type UI struct {
 	canvas *canvas
 }
@@ -77,7 +81,7 @@ func (u *UI) Terminate() {
 	glfw.Terminate()
 }
 
-func (u *UI) Draw(drawer ebiten.GraphicsContextDrawer) error {
+func (u *UI) Draw(drawer GraphicsContextDrawer) error {
 	return u.canvas.draw(drawer)
 }
 
diff --git a/run.go b/runner/run.go
similarity index 85%
rename from run.go
rename to runner/run.go
index af2d17547..7ebf621ee 100644
--- a/run.go
+++ b/runner/run.go
@@ -14,9 +14,11 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package ebiten
+package runner
 
 import (
+	"github.com/hajimehoshi/ebiten"
+	"github.com/hajimehoshi/ebiten/internal/glfw"
 	"os"
 	"os/signal"
 	"syscall"
@@ -25,13 +27,14 @@ import (
 
 type Game interface {
 	Update() error
-	Draw(context GraphicsContext) error
+	Draw(context ebiten.GraphicsContext) error
 }
 
 // Run runs the game. Basically, this function executes ui.Start() at the start,
 // calls ui.DoEvent(), game.Update() and game.Draw() at a regular interval, and finally
 // calls ui.Terminate().
-func Run(ui UI, game Game, width, height, scale int, title string, fps int) error {
+func Run(game Game, width, height, scale int, title string, fps int) error {
+	ui := new(glfw.UI)
 	if err := ui.Start(width, height, scale, title); err != nil {
 		return err
 	}
diff --git a/ui.go b/ui.go
deleted file mode 100644
index 1c44212ee..000000000
--- a/ui.go
+++ /dev/null
@@ -1,29 +0,0 @@
-/*
-Copyright 2014 Hajime Hoshi
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-package ebiten
-
-type UI interface {
-	Start(widht, height, scale int, title string) error
-	DoEvents()
-	Terminate()
-	Draw(drawer GraphicsContextDrawer) error
-	IsClosed() bool
-}
-
-type GraphicsContextDrawer interface {
-	Draw(d GraphicsContext) error
-}