diff --git a/README.md b/README.md
index 78be56fed8ec350075affbac071dc5e9788bfd0d..5c5dcab24ac2d82b9162769b25c8a1c5ff763217 100644
--- a/README.md
+++ b/README.md
@@ -1,9 +1,67 @@
 # 1 minute introduction
 
+## requirements
+- docker
+- nightly toolchain
+
+## usage
+
 ``` console
+$ systemctl start docker.service # if not already started/enabled
+
 $ cargo install --path cargo-klee # add -f, if already installed
 
 $ cd klee-examples
 
 $ cargo klee --example foo --release
+
+KLEE: output directory is "/mnt/target/release/examples/klee-out-0"
+KLEE: Using STP solver backend
+KLEE: ERROR: /home/pln/klee/klee-rust/klee/src/lib.rs:24: abort failure
+KLEE: NOTE: now ignoring this error at this location
+
+KLEE: done: total instructions = 20
+KLEE: done: completed paths = 2
+KLEE: done: generated tests = 2
+
+$ more target/release/examples/klee-out-0/test000001.abort.err
+Error: abort failure
+File: /home/pln/klee/klee-rust/klee/src/lib.rs
+Line: 24
+assembly.ll line: 76
+Stack:
+        #000000076 in _ZN4core9panicking9panic_fmt17hc7d7358b749037fdE () at /home/pln/klee/klee-rust/klee/src/lib.rs:24
+        #100000070 in _ZN4core9panicking5panic17h4680eb5ae9b0e3d0E () at HOME/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/libcore/pani
+cking.rs:51
+        #200000044 in main (=1, =94362321163792) at PWD/klee-examples/examples/foo.rs:22
+
 ```
+
+The error found is at line 22.
+
+``` rust
+
+#![no_std]
+
+#[macro_use]
+extern crate klee;
+
+use core::ptr;
+
+fn main() {
+    let u = ksymbol!("u");
+
+    unsafe {
+        ptr::read_volatile(&f2(f1(u)));
+    }
+}
+
+// add 1 wrapping
+fn f1(u: u8) -> u8 {
+    u.wrapping_add(1)
+}
+
+fn f2(u: u8) -> u8 {
+    100 / u // <- error found here is a Rust div 0 panic! .
+}
+```
\ No newline at end of file
diff --git a/rls1509755957780.log b/rls1509755957780.log
deleted file mode 100644
index a29dede1f0aa9fb441095f9c518bbd6a570dae8a..0000000000000000000000000000000000000000
--- a/rls1509755957780.log
+++ /dev/null
@@ -1,6 +0,0 @@
-error: expected expression, found `+`
-  --> stdin:22:11
-   |
-22 |         j++;
-   |           ^
-