diff --git a/src/components/Statement.vue b/src/components/Statement.vue
index 8712aab..05b4a2e 100644
--- a/src/components/Statement.vue
+++ b/src/components/Statement.vue
@@ -6,12 +6,11 @@ import Katex from './Katex.vue'
 
 const props = defineProps<{
   statement: MathStatement,
-  evaluation: EvaluationResult,
-  renderVersion: number,
+  evaluation?: EvaluationResult,
 }>()
 
 const getValueStatement = (): Maybe<MathStatement> => {
-  const value = props.evaluation.statements[props.statement.id]
+  const value = props.evaluation?.statements?.[props.statement.id]
   if ( value ) {
     return MathStatement.temp(String(value))
   }
@@ -48,7 +47,7 @@ computed(() => value = getValueStatement())
 </style>
 
 <template>
-  <div class="math-statement">
+  <div class="math-statement" style="background: white">
     <div class="content">
       <Katex :statement="statement" size="big"/>
       <div class="result" v-if="value">
diff --git a/src/pages/Editor.vue b/src/pages/Editor.vue
index 9e97186..214d829 100644
--- a/src/pages/Editor.vue
+++ b/src/pages/Editor.vue
@@ -1,14 +1,58 @@
 <script setup lang="ts">
-import { ref } from "vue";
-import WrapperBox from "../components/WrapperBox.vue";
-import TextBox from "../components/TextBox.vue";
+import { ref } from 'vue'
+import { v4 as uuidv4 } from 'uuid'
+import WrapperBox from '../components/WrapperBox.vue'
+import {MathPage} from '../support/page'
+import {MathStatement} from '../support/parse'
+import Katex from '../components/Katex.vue'
+import {EvaluationResult, StatementID} from '../types'
+import Statement from '../components/Statement.vue'
+import VarDeclEditor from './VarDeclEditor.vue'
+import ExpressionEditor from './ExpressionEditor.vue'
+import TextBox from '../components/TextBox.vue'
 
+const math = new MathPage(uuidv4())
+const statements = ref<MathStatement[]>([])
+const evaluation = ref<EvaluationResult|undefined>()
+const statementsKey = ref<string>(uuidv4())
 const leftDrawerOpen = ref(false);
 
 function toggleLeftDrawer() {
   leftDrawerOpen.value = !leftDrawerOpen.value;
 }
 
+const newVariableModalOpen = ref(false)
+const openNewVariableDeclModal = () => {
+  newVariableModalOpen.value = true
+}
+
+const newExpressionModalOpen = ref(false)
+const openNewExpressionModal = () => {
+  newExpressionModalOpen.value = true
+}
+
+const updateStatements = () => {
+  statements.value = math.getStatements()
+  try {
+    evaluation.value = math.evaluate()
+  } catch (_) {
+    evaluation.value = undefined
+  }
+  statementsKey.value = uuidv4()
+}
+
+const saveNewVariable = (stmt: MathStatement) => {
+  math.addStatement(stmt)
+  newVariableModalOpen.value = false
+  updateStatements()
+}
+
+const saveNewExpression = (stmt: MathStatement) => {
+  math.addStatement(stmt)
+  newExpressionModalOpen.value = false
+  updateStatements()
+}
+
 /*
   Rich Text Stuff
 */
@@ -67,6 +111,51 @@ function richUpdateValue() {
     </q-drawer>
 
     <q-page-container id="editor" style="display: flex">
+<!--      <WrapperBox />-->
+
+      <span v-for="statement in statements">
+        <Draggable
+            :grid="[25, 25]"
+        >
+          <Statement
+            :key="statementsKey"
+            :statement="statement"
+            :evaluation="evaluation"
+          />
+        </Draggable>
+      </span>
+
+      <q-dialog v-model="newVariableModalOpen">
+        <VarDeclEditor
+          v-on:save="s => saveNewVariable(s)"
+        />
+      </q-dialog>
+
+      <q-dialog v-model="newExpressionModalOpen">
+        <ExpressionEditor
+          v-on:save="s => saveNewExpression(s)"
+        />
+      </q-dialog>
+
+      <q-page-sticky position="bottom-right" :offset="[32, 32]">
+        <q-fab color="primary" icon="add" direction="left">
+          <q-fab-action
+              color="secondary"
+              label="x"
+              label-style="font-family: serif; font-size: 1.4em; padding: 0"
+              title="Add a variable declaration"
+              @click="() => openNewVariableDeclModal()"
+          />
+          <q-fab-action
+            color="secondary"
+            icon="code"
+            label-style="font-family: serif; font-size: 1.4em; padding: 0"
+            title="Add an expression"
+            @click="() => openNewExpressionModal()"
+          />
+        </q-fab>
+      </q-page-sticky>
+
       <q-dialog v-model="richEditModal">
         <q-card>
           <q-editor v-model="richEditExpression" min-height="5rem" />
diff --git a/src/pages/ExpressionEditor.vue b/src/pages/ExpressionEditor.vue
new file mode 100644
index 0000000..6fffc12
--- /dev/null
+++ b/src/pages/ExpressionEditor.vue
@@ -0,0 +1,78 @@
+<script setup lang="ts">
+import {defineEmits, ref} from 'vue'
+import {MathStatement} from '../support/parse'
+import Katex from '../components/Katex.vue'
+import { v4 as uuidv4 } from 'uuid'
+import {StatementID} from '../types'
+
+const emit = defineEmits<{
+  (eventName: 'save', statement: MathStatement): void
+}>()
+
+const expressionPreview = ref(MathStatement.temp(''))
+const expressionPreviewKey = ref(uuidv4())
+const expressionError = ref<string|undefined>(undefined)
+const expressionValue = ref<string>('')
+
+const updateExpressionPreview = () => {
+  const previewStmt = MathStatement.temp(expressionValue.value)
+  if ( previewStmt.isValid() ) {
+    expressionPreview.value = MathStatement.temp(expressionValue.value)
+    expressionPreviewKey.value = uuidv4()
+  }
+}
+
+const validateExpression = () => {
+  const stmt = MathStatement.temp(expressionValue.value)
+  if ( !stmt.isValid() ) {
+    return 'The expression is invalid'
+  }
+
+  if ( stmt.defines().length > 0 ) {
+    return 'Expressions cannot declare variables'
+  }
+}
+
+const saveExpression = () => {
+  expressionError.value = validateExpression()
+  if ( expressionError.value ) {
+    return
+  }
+
+  emit('save', new MathStatement(
+      uuidv4() as StatementID,
+      expressionValue.value
+  ))
+}
+</script>
+
+<template>
+  <q-card>
+    <q-card-section>
+      <div style="display: flex; justify-content: center">
+        <Katex
+          :key="expressionPreviewKey"
+          :statement="expressionPreview"
+        />
+      </div>
+    </q-card-section>
+    <q-card-section v-if="expressionError">
+      <div style="color: darkred; font-weight: bold">{{ expressionError }}</div>
+    </q-card-section>
+    <q-card-section>
+      <q-input
+        v-model="expressionValue"
+        v-on:update:model-value="() => updateExpressionPreview()"
+        outlined
+        autogrow
+        type="textarea"
+        autofocus
+        label="Expression"
+      />
+    </q-card-section>
+    <q-card-actions align="right" class="text-primary">
+      <q-btn flat label="Cancel" v-close-popup></q-btn>
+      <q-btn flat label="Save" @click="() => saveExpression()"></q-btn>
+    </q-card-actions>
+  </q-card>
+</template>
diff --git a/src/pages/Scratch.vue b/src/pages/Scratch.vue
index 08c4cba..6e54ad8 100644
--- a/src/pages/Scratch.vue
+++ b/src/pages/Scratch.vue
@@ -10,7 +10,6 @@
   const stmt1Id = page.addRaw('x = y+3/4')
   const stmt2Id = page.addRaw('y = 9')
   const evaluation = page.evaluate()
-  let renderVersion = 0
 
   const stmt = page.getStatement(stmt1Id)
   console.log({page, stmt1Id})
@@ -69,6 +68,5 @@
     v-on:edit="() => stmt ? editStatement(stmt) : {}"
     :statement="stmt"
     :evaluation="evaluation"
-    :render-version="renderVersion"
   />
 </template>
diff --git a/src/pages/VarDeclEditor.vue b/src/pages/VarDeclEditor.vue
new file mode 100644
index 0000000..a8f545f
--- /dev/null
+++ b/src/pages/VarDeclEditor.vue
@@ -0,0 +1,94 @@
+<script setup lang="ts">
+import {ref} from 'vue'
+import {MathStatement} from '../support/parse'
+import {v4 as uuidv4} from 'uuid'
+import Katex from '../components/Katex.vue'
+import {StatementID} from '../types'
+
+const emit = defineEmits<{
+  (eventName: 'save', statement: MathStatement): void,
+}>()
+
+const newVariablePreview = ref(MathStatement.temp('? = ?'))
+let newVariablePreviewKey = ref(uuidv4())
+const newVariableModalError = ref<string|undefined>(undefined)
+const newVariableName = ref('')
+const newVariableValue = ref('')
+
+const updateNewVariablePreview = () => {
+  const previewStmt = MathStatement.temp(`${newVariableName.value} = ${newVariableValue.value}`)
+  if ( previewStmt.isValid() ) {
+    newVariablePreview.value = MathStatement.temp(`${newVariableName.value} = ${newVariableValue.value}`)
+    newVariablePreviewKey.value = uuidv4()
+  }
+}
+
+const validateNewVariable = () => {
+  if ( !newVariableName.value ) {
+    return 'Missing variable name'
+  }
+
+  if ( !newVariableValue.value ) {
+    return 'Missing variable value'
+  }
+
+  const stmt = MathStatement.temp(`${newVariableName.value} = ${newVariableValue.value}`)
+  if ( !stmt.isValid() ) {
+    return 'Assignment is invalid'
+  }
+
+  if ( !stmt.isNotRecursive() ) {
+    return 'A variable may not reference itself'
+  }
+}
+
+const saveNewVariable = () => {
+  newVariableModalError.value = validateNewVariable()
+  if ( newVariableModalError.value ) {
+    return
+  }
+
+  emit('save', new MathStatement(
+      uuidv4() as StatementID,
+      `${newVariableName.value} = ${newVariableValue.value}`
+  ))
+}
+</script>
+
+<template>
+  <q-card>
+    <q-card-section>
+      <div style="display: flex; justify-content: center">
+        <Katex
+          :key="newVariablePreviewKey"
+          :statement="newVariablePreview"
+        />
+      </div>
+    </q-card-section>
+    <q-card-section v-if="newVariableModalError">
+      <div style="color: darkred; font-weight: bold">{{ newVariableModalError }}</div>
+    </q-card-section>
+    <q-card-section>
+      <q-input
+        v-model="newVariableName"
+        v-on:update:model-value="() => updateNewVariablePreview()"
+        outlined
+        autofocus
+        label="Variable name"
+      />
+      <br>
+      <q-input
+        v-model="newVariableValue"
+        v-on:update:model-value="() => updateNewVariablePreview()"
+        outlined
+        type="textarea"
+        autogrow
+        label="Value"
+      />
+    </q-card-section>
+    <q-card-actions align="right" class="text-primary">
+      <q-btn flat label="Cancel" v-close-popup></q-btn>
+      <q-btn flat label="Save" @click="() => saveNewVariable()"></q-btn>
+    </q-card-actions>
+  </q-card>
+</template>
diff --git a/src/support/page.ts b/src/support/page.ts
index 3e77930..b4e60fa 100644
--- a/src/support/page.ts
+++ b/src/support/page.ts
@@ -16,6 +16,11 @@ export class MathPage {
         public readonly id: string,
     ) {}
 
+    /** Get all defined statements. */
+    getStatements(): MathStatement[] {
+        return Object.values(this.statements)
+    }
+
     /** Get a statement by ID if it exists. */
     getStatement(id: StatementID): Maybe<MathStatement> {
         return this.statements[id]
diff --git a/src/support/parse.ts b/src/support/parse.ts
index 4245dc2..f5d96da 100644
--- a/src/support/parse.ts
+++ b/src/support/parse.ts
@@ -324,4 +324,18 @@ export class MathStatement {
     uses(): math.SymbolNode[] {
         return (new RValSymbolWalk()).walk(this.parse())
     }
+
+    /** Returns true if the definition is correctly non-recursive. */
+    isNotRecursive(): boolean {
+        const uses = this.uses()
+        const defines = this.defines()
+
+        for ( const define of defines ) {
+            if ( uses.some(x => x.name === define.name) ) {
+                return false
+            }
+        }
+
+        return true
+    }
 }
diff --git a/vite.config.ts b/vite.config.ts
index 3bc00d8..96e978b 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -9,6 +9,9 @@ export default defineConfig({
             '/api': {
                 target: 'http://localhost:8000/',
             },
+            '/auth': {
+                target: 'http://localhost:8000/',
+            },
         },
     },
     plugins: [