diff --git a/.gitignore b/.gitignore
index e3e4b7c..dba9fdb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,61 @@
- 
+ # Prerequisites
+*.d
+
+# Object files
+*.o
+*.ko
+*.obj
+*.elf
+
+# Linker output
+*.ilk
+*.map
+*.exp
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Libraries
+*.lib
+*.a
+*.la
+*.lo
+
+# Shared objects (inc. Windows DLLs)
+*.dll
+*.so
+*.so.*
+*.dylib
+
+# Executables
+*.exe
+*.out
+*.app
+*.i*86
+*.x86_64
+*.hex
+
+# Debug files
+*.dSYM/
+*.su
+*.idb
+*.pdb
+
+# Kernel Module Compile Results
+*.mod*
+*.cmd
+.tmp_versions/
+modules.order
+Module.symvers
+Mkfile.old
+dkms.conf
+
+# CCLS
+.ccls/
+.ccls-cache/
+
+# Scheme
 *.ss~
 *.ss#*
 .#*.ss
diff --git a/how_to_design_programs/test.scm b/how_to_design_programs/test.scm
new file mode 100644
index 0000000..6f1f7b4
--- /dev/null
+++ b/how_to_design_programs/test.scm
@@ -0,0 +1 @@
+#lang racket