diff --git a/bf/fibonacci.bf b/bf/fibonacci.bf
index ac429e9..85bdace 100644
--- a/bf/fibonacci.bf
+++ b/bf/fibonacci.bf
@@ -4,3 +4,6 @@
             [>+<-[>+<-[>+<-[>[-]>+>+<<<-[>+<-]]]]]]]]]]]+>>>
     ]<<<
 ]
+This program doesn't terminate; you will have to kill it.
+Daniel B Cristofani (cristofdathevanetdotcom)
+http://www.hevanet.com/cristofd/brainfuck/
diff --git a/bf/game_of_life.bf b/bf/game_of_life.bf
new file mode 100644
index 0000000..e068233
--- /dev/null
+++ b/bf/game_of_life.bf
@@ -0,0 +1,38 @@
+[life.b -- John Horton Conway's Game of Life
+(c) 2021 Daniel B. Cristofani
+http://brainfuck.org/]
+
+>>>->+>+++++>(++++++++++)[[>>>+<<<-]>+++++>+>>+[<<+>>>>>+<<<-]<-]>>>>[
+  [>>>+>+<<<<-]+++>>+[<+>>>+>+<<<-]>>[>[[>>>+<<<-]<]<<++>+>>>>>>-]<-
+]+++>+>[[-]<+<[>+++++++++++++++++<-]<+]>>[
+  [+++++++++.-------->>>]+[-<<<]>>>[>>,----------[>]<]<<[
+    <<<[
+      >--[<->>+>-<<-]<[[>>>]+>-[+>>+>-]+[<<<]<-]>++>[<+>-]
+      >[[>>>]+[<<<]>>>-]+[->>>]<-[++>]>[------<]>+++[<<<]>
+    ]<
+  ]>[
+    -[+>>+>-]+>>+>>>+>[<<<]>->+>[
+      >[->+>+++>>++[>>>]+++<<<++<<<++[>>>]>>>]<<<[>[>>>]+>>>]
+      <<<<<<<[<<++<+[-<<<+]->++>>>++>>>++<<<<]<<<+[-<<<+]+>->>->>
+    ]<<+<<+<<<+<<-[+<+<<-]+<+[
+      ->+>[-<-<<[<<<]>[>>[>>>]<<+<[<<<]>-]]
+      <[<[<[<<<]>+>>[>>>]<<-]<[<<<]]>>>->>>[>>>]+>
+    ]>+[-<<[-]<]-[
+      [>>>]<[<<[<<<]>>>>>+>[>>>]<-]>>>[>[>>>]<<<<+>[<<<]>>-]>
+    ]<<<<<<[---<-----[-[-[<->>+++<+++++++[-]]]]<+<+]>
+  ]>>
+]
+
+[This program simulates the Game of Life cellular automaton.
+
+It duplicates the interface of the classic program at
+http://www.linusakesson.net/programming/brainfuck/index.php,
+but this program was written from scratch.
+
+Type e.g. "be" to toggle the fifth cell in the second row, "q" to quit,
+or a bare linefeed to advance one generation.
+
+Grid wraps toroidally. Board size in parentheses in first line (2-166 work).
+
+This program is licensed under a Creative Commons Attribution-ShareAlike 4.0
+International License (http://creativecommons.org/licenses/by-sa/4.0/).]
diff --git a/bf/helloworld.bf b/bf/hello_world.bf
similarity index 100%
rename from bf/helloworld.bf
rename to bf/hello_world.bf
diff --git a/lox/bf.lox b/lox/bf.lox
index e43f8b9..dd99608 100644
--- a/lox/bf.lox
+++ b/lox/bf.lox
@@ -68,7 +68,7 @@ class Interpreter {
       }
 
       if (instruction == ",") {
-
+        tape.current.data = promptAscii("> ");
       }
 
       if (instruction == "[" and tape.current.data == 0) {
@@ -96,5 +96,5 @@ class Interpreter {
   }
 }
 
-var interpreter = Interpreter("bf/helloworld.bf");
+var interpreter = Interpreter("bf/game_of_life.bf");
 interpreter.run();
diff --git a/lox/read_ascii.lox b/lox/read_ascii.lox
new file mode 100644
index 0000000..07e18b1
--- /dev/null
+++ b/lox/read_ascii.lox
@@ -0,0 +1,2 @@
+var a = promptAscii("> ");
+print a;
diff --git a/src/native_functions.rs b/src/native_functions.rs
index 2e61e13..b33ab72 100644
--- a/src/native_functions.rs
+++ b/src/native_functions.rs
@@ -187,7 +187,7 @@ impl Callable for AsciiOut {
 struct PromptAscii;
 impl Callable for PromptAscii {
     fn name(&self) -> String {
-        "prompt_ascii".into()
+        "promptAscii".into()
     }
 
     fn arity(&self) -> usize {
@@ -207,14 +207,17 @@ impl Callable for PromptAscii {
             .first()
             .ok_or(CallingError::CallFailed("arg not readable".into()))?;
         if let Value::String(prompt) = prompt {
-            print!("{prompt} ");
-            stdout().flush();
+            print!("{prompt}");
+            stdout()
+                .flush()
+                .map_err(|e| CallingError::CallFailed(e.to_string()))?;
 
             let mut buffer = [0; 1];
-            stdin().read_exact(&mut buffer);
+            stdin()
+                .read_exact(&mut buffer)
+                .map_err(|e| CallingError::CallFailed(e.to_string()))?;
 
-            todo!()
-            // Ok(Value::Number(buffer[0] as char))
+            Ok(Value::Number(OrderedFloat(buffer[0] as f64)))
         } else {
             Err(CallingError::CallFailed("prompt must be a string".into()))
         }
@@ -241,7 +244,7 @@ pub fn all() -> Vec<(String, Value)> {
             Value::Callable((Rc::new(ReadFile {}), CallableType::Function)),
         ),
         (
-            "prompt".into(),
+            "promptAscii".into(),
             Value::Callable((Rc::new(PromptAscii {}), CallableType::Function)),
         ),
     ]