diff --git a/src/App/App.tsx b/src/App/App.tsx
index 00eb173..d7d119a 100644
--- a/src/App/App.tsx
+++ b/src/App/App.tsx
@@ -45,6 +45,7 @@ export function App() {
   const [time, setTime] = useState<TimeMode>({kind: "paused", simtime: 0});
   const [modal, setModal] = useState<ReactElement|null>(null);
   const [plantName, setPlantName] = usePersistentState("plant", "dummy");
+  const [zoom, setZoom] = usePersistentState("zoom", 1);
 
   const plant = plants.find(([pn, p]) => pn === plantName)![1];
 
@@ -248,12 +249,12 @@ export function App() {
           >
             <TopPanel
               rt={rtIdx === undefined ? undefined : rt[rtIdx]}
-              {...{rtIdx, ast, time, setTime, onUndo, onRedo, onInit, onClear, onRaise, onBack, mode, setMode, setModal}}
+              {...{rtIdx, ast, time, setTime, onUndo, onRedo, onInit, onClear, onRaise, onBack, mode, setMode, setModal, zoom, setZoom}}
             />
           </Box>
           {/* Below the top bar: Editor */}
           <Box sx={{flexGrow:1, overflow: "auto"}}>
-            <VisualEditor {...{state: editorState, setState: setEditorState, ast, setAST, rt: rt.at(rtIdx!), setRT, errors, setErrors, mode, highlightActive, highlightTransitions, setModal, makeCheckPoint}}/>
+            <VisualEditor {...{state: editorState, setState: setEditorState, ast, setAST, rt: rt.at(rtIdx!), setRT, errors, setErrors, mode, highlightActive, highlightTransitions, setModal, makeCheckPoint, zoom}}/>
           </Box>
         </Stack>
       </Box>
diff --git a/src/App/TopPanel.tsx b/src/App/TopPanel.tsx
index 67f6c1e..da17fc5 100644
--- a/src/App/TopPanel.tsx
+++ b/src/App/TopPanel.tsx
@@ -15,6 +15,8 @@ import UndoIcon from '@mui/icons-material/Undo';
 import RedoIcon from '@mui/icons-material/Redo';
 import InfoOutlineIcon from '@mui/icons-material/InfoOutline';
 import KeyboardIcon from '@mui/icons-material/Keyboard';
+import ZoomInIcon from '@mui/icons-material/ZoomIn';
+import ZoomOutIcon from '@mui/icons-material/ZoomOut';
 
 import { formatTime } from "./util";
 import { InsertMode } from "../VisualEditor/VisualEditor";
@@ -38,9 +40,11 @@ export type TopPanelProps = {
   mode: InsertMode,
   setMode: Dispatch<SetStateAction<InsertMode>>,
   setModal: Dispatch<SetStateAction<ReactElement|null>>,
+  zoom: number,
+  setZoom: Dispatch<SetStateAction<number>>,
 }
 
-export function TopPanel({rt, rtIdx, time, setTime, onUndo, onRedo, onInit, onClear, onRaise, onBack, ast, mode, setMode, setModal}: TopPanelProps) {
+export function TopPanel({rt, rtIdx, time, setTime, onUndo, onRedo, onInit, onClear, onRaise, onBack, ast, mode, setMode, setModal, zoom, setZoom}: TopPanelProps) {
   const [displayTime, setDisplayTime] = useState("0.000");
   const [timescale, setTimescale] = useState(1);
   const [showKeys, setShowKeys] = usePersistentState("shortcuts", true);
@@ -99,6 +103,14 @@ export function TopPanel({rt, rtIdx, time, setTime, onUndo, onRedo, onInit, onCl
           e.preventDefault();
           onRedo();
         }
+        if (e.key === "+") {
+          e.preventDefault();
+          onZoomIn();
+        }
+        if (e.key === "-") {
+          e.preventDefault();
+          onZoomOut();
+        }
       }
     };
     window.addEventListener("keydown", onKeyDown);
@@ -123,6 +135,13 @@ export function TopPanel({rt, rtIdx, time, setTime, onUndo, onRedo, onInit, onCl
     }
   }, [time]);
 
+  function onZoomIn() {
+    setZoom(zoom => Math.min(zoom * 1.25, 4));
+  }
+  function onZoomOut() {
+    setZoom(zoom => Math.max(zoom / 1.25, 1/4));
+  }
+
   function onChangePaused(paused: boolean, wallclktime: number) {
     setTime(time => {
       if (paused) {
@@ -189,6 +208,16 @@ export function TopPanel({rt, rtIdx, time, setTime, onUndo, onRedo, onInit, onCl
       &emsp;
     </div>
 
+    {/* zoom */}
+    <div className="toolbarGroup">
+      <KeyInfo keyInfo={<><kbd>Ctrl</kbd>+<kbd>+</kbd></>}>
+        <button title="zoom in" onClick={onZoomIn}><ZoomInIcon fontSize="small"/></button>
+      </KeyInfo>
+      <KeyInfo keyInfo={<><kbd>Ctrl</kbd>+<kbd>-</kbd></>}>
+        <button title="zoom out" onClick={onZoomOut}><ZoomOutIcon fontSize="small"/></button>
+      </KeyInfo>
+      &emsp;
+    </div>
 
     {/* undo / redo */}
     <div className="toolbarGroup">
diff --git a/src/Plant/DigitalWatch/DigitalWatch.tsx b/src/Plant/DigitalWatch/DigitalWatch.tsx
index 376cb14..9d41279 100644
--- a/src/Plant/DigitalWatch/DigitalWatch.tsx
+++ b/src/Plant/DigitalWatch/DigitalWatch.tsx
@@ -45,19 +45,19 @@ export function DigitalWatch({light, h, m, s, alarm, callbacks}: DigitalWatchPro
 
       <text x="111" y="126" dominantBaseline="middle" textAnchor="middle" fontFamily="digital-font" fontSize={28} style={{whiteSpace:'preserve'}}>{hhmmss}</text>
     
-      <rect x="0" y="59" width="16" height="16" fill="#fff" fill-opacity="0" 
+      <rect x="0" y="59" width="16" height="16" fill="#fff" fillOpacity="0" 
         onMouseDown={() => callbacks.onTopLeftPressed()}
         onMouseUp={() => callbacks.onTopLeftReleased()}
       />
-      <rect x="206" y="57" width="16" height="16" fill="#fff" fill-opacity="0"
+      <rect x="206" y="57" width="16" height="16" fill="#fff" fillOpacity="0"
         onMouseDown={() => callbacks.onTopRightPressed()}
         onMouseUp={() => callbacks.onTopRightReleased()}
       />
-      <rect x="0" y="158" width="16" height="16" fill="#fff" fill-opacity="0"
+      <rect x="0" y="158" width="16" height="16" fill="#fff" fillOpacity="0"
         onMouseDown={() => callbacks.onBottomLeftPressed()}
         onMouseUp={() => callbacks.onBottomLeftReleased()}
       />
-      <rect x="208" y="158" width="16" height="16" fill="#fff" fill-opacity="0"
+      <rect x="208" y="158" width="16" height="16" fill="#fff" fillOpacity="0"
         onMouseDown={() => callbacks.onBottomRightPressed()}
         onMouseUp={() => callbacks.onBottomRightReleased()}
       />
diff --git a/src/VisualEditor/VisualEditor.tsx b/src/VisualEditor/VisualEditor.tsx
index 392a4a8..d76fec9 100644
--- a/src/VisualEditor/VisualEditor.tsx
+++ b/src/VisualEditor/VisualEditor.tsx
@@ -4,7 +4,7 @@ import { Statechart } from "../statecharts/abstract_syntax";
 import { Arrow, ArrowPart, Diamond, History, Rountangle, RountanglePart, Text } from "../statecharts/concrete_syntax";
 import { parseStatechart, TraceableError } from "../statecharts/parser";
 import { BigStep } from "../statecharts/runtime_types";
-import { ArcDirection, Line2D, Rect2D, Vec2D, addV2D, arcDirection, area, getBottomSide, getLeftSide, getRightSide, getTopSide, isEntirelyWithin, normalizeRect, subtractV2D, transformLine, transformRect } from "./geometry";
+import { ArcDirection, Line2D, Rect2D, Vec2D, addV2D, arcDirection, area, getBottomSide, getLeftSide, getRightSide, getTopSide, isEntirelyWithin, normalizeRect, scaleV2D, subtractV2D, transformLine, transformRect } from "./geometry";
 import { MIN_ROUNTANGLE_SIZE } from "./parameters";
 import { getBBoxInSvgCoords } from "./svg_helper";
 import { ArrowSVG } from "./ArrowSVG";
@@ -73,9 +73,10 @@ type VisualEditorProps = {
   highlightTransitions: string[],
   setModal: Dispatch<SetStateAction<ReactElement|null>>,
   makeCheckPoint: () => void;
+  zoom: number;
 };
 
-export function VisualEditor({state, setState, ast, setAST, rt, errors, setErrors, mode, highlightActive, highlightTransitions, setModal, makeCheckPoint}: VisualEditorProps) {
+export function VisualEditor({state, setState, ast, setAST, rt, errors, setErrors, mode, highlightActive, highlightTransitions, setModal, makeCheckPoint, zoom}: VisualEditorProps) {
 
   const [dragging, setDragging] = useState(false);
 
@@ -163,8 +164,8 @@ export function VisualEditor({state, setState, ast, setAST, rt, errors, setError
   function getCurrentPointer(e: {pageX: number, pageY: number}) {
     const bbox = refSVG.current!.getBoundingClientRect();
     return {
-      x: e.pageX - bbox.left,
-      y: e.pageY - bbox.top,
+      x: (e.pageX - bbox.left)/zoom,
+      y: (e.pageY - bbox.top)/zoom,
     }
   }
 
@@ -293,7 +294,7 @@ export function VisualEditor({state, setState, ast, setAST, rt, errors, setError
     const currentPointer = getCurrentPointer(e);
     if (dragging) {
       // const pointerDelta = subtractV2D(currentPointer, dragging.lastMousePos);
-      const pointerDelta = {x: e.movementX, y: e.movementY};
+      const pointerDelta = {x: e.movementX/zoom, y: e.movementY/zoom};
       setState(state => ({
         ...state,
         rountangles: state.rountangles.map(r => {
@@ -398,7 +399,11 @@ export function VisualEditor({state, setState, ast, setAST, rt, errors, setError
         const shapes = Array.from(refSVG.current?.querySelectorAll("rect, line, circle, text") || []) as SVGGraphicsElement[];
         const shapesInSelection = shapes.filter(el => {
           const bbox = getBBoxInSvgCoords(el, refSVG.current!);
-          return isEntirelyWithin(bbox, normalizedSS);
+          const scaledBBox = {
+            topLeft: scaleV2D(bbox.topLeft, 1/zoom),
+            size: scaleV2D(bbox.size, 1/zoom),
+          }
+          return isEntirelyWithin(scaledBBox, normalizedSS);
         }).filter(el => !el.classList.contains("corner"));
         
         const uidToParts = new Map();
@@ -666,12 +671,16 @@ export function VisualEditor({state, setState, ast, setAST, rt, errors, setError
 
   const rootErrors = errors.filter(({shapeUid}) => shapeUid === "root").map(({message}) => message);
 
-  return <svg width="4000px" height="4000px"
+  const size = 4000*zoom;
+
+  return <svg width={size} height={size}
       className={"svgCanvas"+(active.has("root")?" active":"")+(dragging ? " dragging" : "")}
       onMouseDown={onMouseDown}
       onContextMenu={e => e.preventDefault()}
       ref={refSVG}
 
+      viewBox={`0 0 4000 4000`}
+
       onCopy={onCopy}
       onPaste={onPaste}
       onCut={onCut}
diff --git a/todo.txt b/todo.txt
index 7f519cb..b6e28bc 100644
--- a/todo.txt
+++ b/todo.txt
@@ -45,6 +45,7 @@ TODO
         - stuck in pseudo-state
         - ???
       don't crash and show the error
+    - buttons to rotate selection 90 degrees
 
 - experimental features:
     - multiverse execution history