diff --git a/README.md b/README.md
index f98f8c2..3f562fe 100644
--- a/README.md
+++ b/README.md
@@ -10,10 +10,10 @@ There are two groups of 4 files:
 
 ### Simulations of classical particles in billiards.
 
-1. global_particles.c:    global variables and parameters
-2. sub_part_billiard.c:   drawing/computation routines common to particle_billiard and drop_billiard
-3. particle_billiard.c:   simulation of a collection of non-interacting particles in a billiard
-4. drop_billiard.c:       simulation of an expanding front of particles
+1. **global_particles.c**:    global variables and parameters
+2. **sub_part_billiard.c**:   drawing/computation routines common to particle_billiard and drop_billiard
+3. **particle_billiard.c**:   simulation of a collection of non-interacting particles in a billiard
+4. **drop_billiard.c**:       simulation of an expanding front of particles
 
 - Create subfolders 'tif_part', 'tif_drop'
 - Customize constants at beginning of .c file
@@ -29,11 +29,11 @@ ffmpeg -i part.%05d.tif -vcodec libx264 part.mp4
 
 ### Simulations of wave equation, heat equation and Schrodinger equation.
 
-1. global_pdes.c:     global variables and parameters
-2. sub_wave.c:        drawing/computation routines common to wave_billiard, heat and schrodinger
-3. wave_billiard.c:   simulation of the (linear) wave equation
-4. heat.c:            simulation of the heat equation, with optional drawing of gradient field lines
-5. schrodinger.c:     simulation of the Schrodinger equation
+1. **global_pdes.c**:     global variables and parameters
+2. **sub_wave.c**:        drawing/computation routines common to wave_billiard, heat and schrodinger
+3. **wave_billiard.c**:   simulation of the (linear) wave equation
+4. **heat.c**:            simulation of the heat equation, with optional drawing of gradient field lines
+5. **schrodinger.c**:     simulation of the Schrodinger equation
 
 - Create subfolders 'tif_wave', 'tif_heat', 'tif_schrod'
 - Customize constants at beginning of .c file