diff --git a/pdf/L11.pdf b/pdf/L11.pdf new file mode 100644 index 0000000..5000a21 Binary files /dev/null and b/pdf/L11.pdf differ diff --git a/pdf/L12.pdf b/pdf/L12.pdf new file mode 100644 index 0000000..029b9ac Binary files /dev/null and b/pdf/L12.pdf differ