diff --git a/init.lua b/init.lua
index 6371ed8..9e12a8b 100644
--- a/init.lua
+++ b/init.lua
@@ -4,6 +4,7 @@ local camera      = require("lib-core.camera")
 local input       = require("lib-core.input")
 local player      = require("lib-core.player_control")
 local interaction = require("lib-core.interaction")
+local selection   = require("lib-core.selection")
 
 local demo_map = maps.load("maps/demo.map.json")
 maps.set_current(demo_map)
@@ -31,6 +32,14 @@ input.bind("pan_left",        { "a", "left" })
 input.bind("pan_right",       { "d", "right" })
 input.bind("pan_up",          { "w", "up" })
 input.bind("pan_down",        { "s", "down" })
+-- P.3.6: Selection bindings
+input.bind("lmb",        { "mouse_left" })
+input.bind("mod_add",    { "shift" })
+input.bind("mod_toggle", { "ctrl" })
+
+selection.bind_action("lmb")
+selection.bind_modifier_add("mod_add")
+selection.bind_modifier_toggle("mod_toggle")
 
 camera.bind_pan_keys("pan_left", "pan_right", "pan_up", "pan_down")
 camera.bind_pan_drag("pan_drag")
@@ -51,6 +60,17 @@ local PLAYER_R, PLAYER_G, PLAYER_B = 200, 60, 80
 local sign = { x = 144, y = 144, text = "Hier steht: Willkommen im Spine." }
 local SIGN_R, SIGN_G, SIGN_B = 220, 200, 60
 
+-- P.3.6: 6 stones as selectables (demo for click/box-select + modifiers).
+-- Positions distributed across walkable map area; sizes uniform 20×20.
+local stones = {
+    { x =  64, y =  96, w = 20, h = 20, color = {120, 120, 140} },
+    { x = 224, y =  96, w = 20, h = 20, color = {120, 120, 140} },
+    { x =  96, y = 256, w = 20, h = 20, color = {130, 110, 100} },
+    { x = 320, y = 192, w = 20, h = 20, color = {130, 110, 100} },
+    { x = 192, y = 320, w = 20, h = 20, color = {140, 130, 110} },
+    { x = 384, y = 256, w = 20, h = 20, color = {140, 130, 110} },
+}
+
 -- P.3.5: Free-Cam-Mode state
 local free_cam_mode = false
 
@@ -80,21 +100,38 @@ function init(ctx)
     end)
     engine.print(string.format("interaction: %d trigger(s) registered",
         interaction.trigger_count()))
+    -- P.3.6: Register each stone as selectable.
+    for _, s in ipairs(stones) do
+        s.sel_handle = selection.register(function()
+            return { x = s.x, y = s.y, w = s.w, h = s.h }
+        end)
+    end
+    engine.print(string.format("selection: %d selectables registered",
+        selection.count_registered()))
 end
 
 function render(ctx)
     engine.render.clear_color(engine.render.rgb(20, 20, 30))
     camera.begin()
-    r_lib.draw_map()
-    -- draw sign on top of map
-    engine.render.draw_rect(sign.x - 6, sign.y - 6, 12, 12,
-        engine.render.rgb(SIGN_R, SIGN_G, SIGN_B))
-    -- draw player on top of sign
-    local p = player.position()
-    local s = player.size()
-    engine.render.draw_rect(p.x, p.y, s.w, s.h,
-        engine.render.rgb(PLAYER_R, PLAYER_G, PLAYER_B))
+        r_lib.draw_map()
+        -- draw sign on top of map
+        engine.render.draw_rect(sign.x - 6, sign.y - 6, 12, 12,
+            engine.render.rgb(SIGN_R, SIGN_G, SIGN_B))
+        -- P.3.6: draw stones
+        for _, s in ipairs(stones) do
+            engine.render.draw_rect(s.x, s.y, s.w, s.h,
+                engine.render.rgb(s.color[1], s.color[2], s.color[3]))
+        end
+        -- draw player on top of map/stones
+        local p = player.position()
+        local sz = player.size()
+        engine.render.draw_rect(p.x, p.y, sz.w, sz.h,
+            engine.render.rgb(PLAYER_R, PLAYER_G, PLAYER_B))
+        -- P.3.6: highlights over selected entities (world-space)
+        selection.render_highlights()
     camera.finish()
+    -- P.3.6: drag-box overlay (screen-space, after camera.finish)
+    selection.render_drag_box()
 end
 
 function update(ctx, dt)
@@ -120,6 +157,7 @@ function update(ctx, dt)
 
     -- Pan-Summation jeden Frame (keys nur wenn enabled; drag + edge always-on).
     camera.update(dt)
+    selection.update(dt)
 
     if not free_cam_mode then
         -- Follow-cam: set_target jeden Frame -> drag/edge "drift" wird unsichtbar.
diff --git a/manifest.module b/manifest.module
index e3aa406..a1820e5 100644
--- a/manifest.module
+++ b/manifest.module
@@ -7,7 +7,8 @@
     "deps": [
         {"id":"lib-core.maps","version":"0.1.1"},
         {"id":"lib-core.render","version":"0.1.0"},
-        {"id":"lib-core.camera","version":"0.2.0"},
+        {"id":"lib-core.camera","version":"0.3.0"},
+        {"id":"lib-core.selection","version":"0.1.0"},
         {"id":"lib-core.input","version":"0.3.0"},
         {"id":"lib-core.player_control","version":"0.1.0"},
         {"id":"lib-core.interaction","version":"0.1.0"}