diff --git a/apps/tinyproxy_nyash/proxy_server.nyash b/apps/tinyproxy_nyash/proxy_server.nyash
index d52429ce..8bfa522f 100644
--- a/apps/tinyproxy_nyash/proxy_server.nyash
+++ b/apps/tinyproxy_nyash/proxy_server.nyash
@@ -166,7 +166,7 @@ static box Main {
         me.console = new ConsoleBox()
         me.console.log("🚀 Starting Tinyproxy Nyash - Phase 10.1")
         
-        local result = statics.ProxyServer.main()
+        local result = ProxyServer.main()
         
         me.console.log("🏁 Proxy result: " + result)
         return "Phase 10.1 Complete"
diff --git a/src/ast.rs b/src/ast.rs
index a597db1c..d2a40d54 100644
--- a/src/ast.rs
+++ b/src/ast.rs
@@ -250,6 +250,7 @@ pub enum LiteralValue {
     Integer(i64),
     Float(f64),  // 浮動小数点数サポート追加
     Bool(bool),
+    Null,        // null値
     Void,
 }
 
@@ -264,6 +265,7 @@ impl LiteralValue {
             LiteralValue::Integer(i) => Box::new(IntegerBox::new(*i)),
             LiteralValue::Float(f) => Box::new(FloatBox::new(*f)),
             LiteralValue::Bool(b) => Box::new(BoolBox::new(*b)),
+            LiteralValue::Null => Box::new(crate::boxes::null_box::NullBox::new()),
             LiteralValue::Void => Box::new(VoidBox::new()),
         }
     }
@@ -283,6 +285,8 @@ impl LiteralValue {
             Some(LiteralValue::Float(float_box.value))
         } else if let Some(bool_box) = box_val.as_any().downcast_ref::<BoolBox>() {
             Some(LiteralValue::Bool(bool_box.value))
+        } else if box_val.as_any().downcast_ref::<crate::boxes::null_box::NullBox>().is_some() {
+            Some(LiteralValue::Null)
         } else if box_val.as_any().downcast_ref::<VoidBox>().is_some() {
             Some(LiteralValue::Void)
         } else {
@@ -298,6 +302,7 @@ impl fmt::Display for LiteralValue {
             LiteralValue::Integer(i) => write!(f, "{}", i),
             LiteralValue::Float(fl) => write!(f, "{}", fl),
             LiteralValue::Bool(b) => write!(f, "{}", b),
+            LiteralValue::Null => write!(f, "null"),
             LiteralValue::Void => write!(f, "void"),
         }
     }
diff --git a/src/box_arithmetic.rs b/src/box_arithmetic.rs
index 009f3709..bfafc2ec 100644
--- a/src/box_arithmetic.rs
+++ b/src/box_arithmetic.rs
@@ -513,6 +513,14 @@ impl BoxCore for ModuloBox {
     fn fmt_box(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
         write!(f, "ModuloBox[{}]", self.box_id())
     }
+    
+    fn as_any(&self) -> &dyn std::any::Any {
+        self
+    }
+    
+    fn as_any_mut(&mut self) -> &mut dyn std::any::Any {
+        self
+    }
 }
 
 impl NyashBox for ModuloBox {
diff --git a/src/parser/expressions.rs b/src/parser/expressions.rs
index b834083d..091dce6d 100644
--- a/src/parser/expressions.rs
+++ b/src/parser/expressions.rs
@@ -357,6 +357,14 @@ impl NyashParser {
                 })
             }
             
+            TokenType::NULL => {
+                self.advance();
+                Ok(ASTNode::Literal {
+                    value: LiteralValue::Null,
+                    span: Span::unknown(),
+                })
+            }
+            
             TokenType::THIS => {
                 self.advance();
                 Ok(ASTNode::This { span: Span::unknown() })
diff --git a/src/tokenizer.rs b/src/tokenizer.rs
index aa8e04a9..06b96100 100644
--- a/src/tokenizer.rs
+++ b/src/tokenizer.rs
@@ -16,6 +16,7 @@ pub enum TokenType {
     FLOAT(f64),  // 浮動小数点数サポート追加
     TRUE,
     FALSE,
+    NULL,        // null リテラル
     
     // キーワード
     BOX,
@@ -417,6 +418,7 @@ impl NyashTokenizer {
             "or" => TokenType::OR,
             "true" => TokenType::TRUE,
             "false" => TokenType::FALSE,
+            "null" => TokenType::NULL,
             _ => TokenType::IDENTIFIER(identifier),
         }
     }
diff --git a/test_array_length_fix.nyash b/test_array_length_fix.nyash
new file mode 100644
index 00000000..152fc0a8
--- /dev/null
+++ b/test_array_length_fix.nyash
@@ -0,0 +1,43 @@
+// Test for ArrayBox.length() functionality 
+static box ArrayLengthTest {
+    init { console }
+    
+    main() {
+        me.console = new ConsoleBox()
+        me.console.log("🧪 Testing ArrayBox.length() functionality")
+        
+        // Test 1: Empty array
+        local empty_array = new ArrayBox()
+        local empty_length = empty_array.length()
+        me.console.log("Empty array length: " + empty_length)  // Expected: 0
+        
+        // Test 2: Array with elements
+        local test_array = new ArrayBox()
+        test_array.push("first")
+        test_array.push("second") 
+        test_array.push("third")
+        
+        local length_after_push = test_array.length()
+        me.console.log("Array length after 3 pushes: " + length_after_push)  // Expected: 3
+        
+        // Test 3: Array after pop
+        local popped = test_array.pop()
+        me.console.log("Popped element: " + popped)
+        
+        local length_after_pop = test_array.length()
+        me.console.log("Array length after pop: " + length_after_pop)  // Expected: 2
+        
+        // Test 4: Verify elements are still accessible
+        local first_element = test_array.get(0)
+        local second_element = test_array.get(1) 
+        me.console.log("Element at index 0: " + first_element)
+        me.console.log("Element at index 1: " + second_element)
+        
+        // Test 5: Edge case - accessing beyond length
+        local beyond_length = test_array.get(5)
+        me.console.log("Element beyond length: " + beyond_length)  // Expected: null
+        
+        me.console.log("✅ ArrayBox.length() tests completed")
+        return "ArrayBox functionality verified"
+    }
+}
\ No newline at end of file
diff --git a/test_modulo_operator_fix.nyash b/test_modulo_operator_fix.nyash
new file mode 100644
index 00000000..897b4793
--- /dev/null
+++ b/test_modulo_operator_fix.nyash
@@ -0,0 +1,31 @@
+// Test % operator functionality after ModuloBox fix
+static box ModuloTest {
+    init { console }
+    
+    main() {
+        me.console = new ConsoleBox()
+        me.console.log("🧪 Testing % operator after ModuloBox fix")
+        
+        // Test 1: Basic modulo operation
+        local result1 = 10 % 3
+        me.console.log("10 % 3 = " + result1)  // Expected: 1
+        
+        // Test 2: Chip-8 style operations
+        local result2 = 4096 % 4096
+        me.console.log("4096 % 4096 = " + result2)  // Expected: 0
+        
+        local result3 = 256 % 16  
+        me.console.log("256 % 16 = " + result3)   // Expected: 0
+        
+        // Test 3: Common modulo patterns
+        local result4 = 17 % 5
+        me.console.log("17 % 5 = " + result4)    // Expected: 2
+        
+        // Test 4: Zero check (should not crash)
+        local result5 = 42 % 1
+        me.console.log("42 % 1 = " + result5)    // Expected: 0
+        
+        me.console.log("✅ Modulo operator tests completed")
+        return "ModuloBox fix verified"
+    }
+}
\ No newline at end of file
diff --git a/test_null_literal_support.nyash b/test_null_literal_support.nyash
new file mode 100644
index 00000000..0fe71f11
--- /dev/null
+++ b/test_null_literal_support.nyash
@@ -0,0 +1,36 @@
+// Test null literal support
+static box NullLiteralTest {
+    init { console }
+    
+    main() {
+        me.console = new ConsoleBox()
+        me.console.log("🧪 Testing null literal support")
+        
+        // Test 1: Basic null assignment
+        local null_value = null
+        me.console.log("Null value: " + null_value)
+        
+        // Test 2: Null comparison
+        if null_value == null {
+            me.console.log("✅ Null comparison works")
+        } else {
+            me.console.log("❌ Null comparison failed")
+        }
+        
+        // Test 3: Null vs non-null
+        local non_null = "not null"
+        if non_null != null {
+            me.console.log("✅ Non-null comparison works")
+        } else {
+            me.console.log("❌ Non-null comparison failed")
+        }
+        
+        // Test 4: Null in conditions
+        if null_value == null {
+            me.console.log("✅ Null condition evaluation works")
+        }
+        
+        me.console.log("✅ Null literal tests completed")
+        return "Null literal support verified"
+    }
+}
\ No newline at end of file
diff --git a/test_static_box_patterns.nyash b/test_static_box_patterns.nyash
new file mode 100644
index 00000000..ed69cc66
--- /dev/null
+++ b/test_static_box_patterns.nyash
@@ -0,0 +1,71 @@
+// Test for proper static box usage patterns
+static box StaticBoxTest {
+    init { console, test_result }
+    
+    main() {
+        me.console = new ConsoleBox()
+        me.console.log("🧪 Testing proper static box patterns")
+        
+        // ✅ Correct: Call static method directly
+        local result = StaticBoxTest.test_static_method()
+        me.console.log("Static method result: " + result)
+        
+        // ✅ Correct: Access static box fields through me
+        me.test_result = "Static box initialization successful"
+        me.console.log("Static field access: " + me.test_result)
+        
+        me.console.log("✅ Static box pattern tests completed")
+        return "Static box usage verified"
+    }
+    
+    test_static_method() {
+        return "Static method executed successfully"
+    }
+}
+
+// Test proxy server pattern (simplified)
+static box SimpleProxyTest {
+    init { console, port, running }
+    
+    main() {
+        me.console = new ConsoleBox()
+        me.console.log("🌐 Testing simplified proxy server pattern")
+        
+        // ✅ Correct: Initialize static box fields
+        me.port = 8080
+        me.running = true
+        
+        me.console.log("Proxy configured on port: " + me.port)
+        me.console.log("Proxy running status: " + me.running)
+        
+        // ✅ Correct: Call other static methods
+        local startup_result = SimpleProxyTest.simulate_startup()
+        me.console.log("Startup result: " + startup_result)
+        
+        return "Proxy simulation complete"
+    }
+    
+    simulate_startup() {
+        return "Proxy server simulation started successfully"
+    }
+}
+
+// Entry point
+static box Main {
+    init { console }
+    
+    main() {
+        me.console = new ConsoleBox()
+        me.console.log("🚀 Testing Static Box Patterns")
+        
+        // Test both static box patterns
+        local test1_result = StaticBoxTest.main()
+        me.console.log("Test 1: " + test1_result)
+        
+        local test2_result = SimpleProxyTest.main()
+        me.console.log("Test 2: " + test2_result)
+        
+        me.console.log("✅ All static box pattern tests passed")
+        return "Static box tests complete"
+    }
+}
\ No newline at end of file