diff --git a/gas_sim.py b/gas_sim.py
new file mode 100644
index 0000000..5cc53cf
--- /dev/null
+++ b/gas_sim.py
@@ -0,0 +1,30 @@
+from math import hypot
+
+
+class Particle:
+    def __init__(self, pos, vel):
+        self.pos = pos
+        self.vel = vel
+
+    def update(self, dt):
+        self.pos = (self.pos[0] + self.vel[0] * dt, self.pos[1] + self.vel[1] * dt)
+
+
+class GasSim:
+    def __init__(self, particle_radius, particle_compressibility, substeps):
+        self.particle_radius = particle_radius
+        self.particle_compressibility = particle_compressibility
+        self.substeps = substeps
+
+        self.particles = []
+
+    def add_particle(self, pos, vel = (0, 0)):
+        self.particles.append(Particle(pos, vel))
+
+    def return_particles_pos(self):
+        return tuple(particle.pos for particle in self.particles)
+
+    def cursor_particle_collide_test(self, cursor_pos, cursor_radius):
+        for particle in self.particles:
+            if hypot(particle.pos[0] - cursor_pos[0], particle.pos[1] - cursor_pos[1]) <= cursor_radius + self.particle_radius:
+                return True
\ No newline at end of file
diff --git a/main.py b/main.py
new file mode 100644
index 0000000..4dbce2e
--- /dev/null
+++ b/main.py
@@ -0,0 +1,71 @@
+import pygame
+import pygame.gfxdraw
+import gas_sim as gs
+
+##### CONFIG #####
+window_size = (1280, 720)
+
+
+particle_radius_ws = 0.1
+particle_compressibility = 0.5
+
+cursor_radius_ws = 0.1
+
+substeps = 10
+##################
+
+# ws - world space
+# ss - screen space
+
+window_aspect = window_size[0] / window_size[1]
+cursor_radius_ss = cursor_radius_ws * window_size[1]
+
+
+# pygame init
+pygame.init()
+window = pygame.display.set_mode(window_size)
+clock = pygame.time.Clock()
+
+
+
+# gas sim init
+gas_sim = gs.GasSim(particle_radius_ws, particle_compressibility, substeps)
+
+
+
+# main loop
+while True:
+    # events
+    for event in pygame.event.get():
+        if event.type == pygame.QUIT:
+            pygame.quit()
+            quit()
+
+
+    # on mouse down
+    if pygame.mouse.get_pressed()[0]:
+        
+        mouse_pos_ss = pygame.mouse.get_pos()
+
+        mouse_pos_ws = (mouse_pos_ss[0] / window_size[1], mouse_pos_ss[1] / window_size[1])
+
+        # if not colliding with any particles
+        if not gas_sim.cursor_particle_collide_test(mouse_pos_ws, cursor_radius_ws):
+            gas_sim.add_particle(mouse_pos_ws)
+
+
+    window.fill((0, 0, 0))
+
+    # draw cursor
+    cursor_pos = pygame.mouse.get_pos()
+    pygame.gfxdraw.aacircle(window, cursor_pos[0], cursor_pos[1], int(cursor_radius_ss), (255, 255, 255))
+
+    # draw particles
+    for particle_pos in gas_sim.return_particles_pos():
+        particle_pos_ss = (int(particle_pos[0] * window_size[1]), int(particle_pos[1] * window_size[1]))
+        pygame.gfxdraw.aacircle(window, particle_pos_ss[0], particle_pos_ss[1], int(cursor_radius_ss), (255, 255, 255))
+
+
+    # update
+    pygame.display.update()
+    clock.tick(60)
\ No newline at end of file