diff --git a/py/skewed_random_generator.py b/py/skewed_random_generator.py
index e011bff..74c91be 100644
--- a/py/skewed_random_generator.py
+++ b/py/skewed_random_generator.py
@@ -1,4 +1,5 @@
-
+import logging
+import random
 
 #trials = 100              # Number of total trials
 #T  = 20                    # Number of targets
@@ -6,6 +7,46 @@
 #L2 = 10                   # Number of lures (foil) similar to the (N-1)-back
 #D  = trials - L1 - L2 - T  # Number of distractors
 
-def generate(N = 2, trials = 100, T = 20, L1 = 10, L2 = 10):
-  D = trials - T - L1 - L2
-  pass
\ No newline at end of file
+class SkewedRandomGenerator:
+  """Generates random sequence of stimuli for the n-back task. Implementation is based on Ralph (2014)."""
+
+  seq = []
+
+  def __init__(self,
+               N = 2, 
+               alphabet=['A','B','C','D','E','F'], 
+               target='A', 
+               trials = 100, 
+               T = 20, 
+               L1 = 10, 
+               L2 = 10):
+    self.N, self.alphabet, self.target, self.trials, self.T, self.L1, self.L2 = N, alphabet, target, trials, T, L1, L2
+    self.D = trials - T - L1 - L2
+    try:
+      self.alphabet.remove(target)
+    except ValueError:
+      #logging.info('Nice, alphabet does not contain the target stimulus!')
+      pass
+
+  def generate(self):
+
+    pass
+
+  def random_trial(self, trial):
+    rnd = random.randint(1, self.trials - trial + 1)
+    T, L1, L2 = self.T, self.L1, self.L2
+    if rnd < T:
+      self.T -= 1
+      return self.target
+    elif T <= rnd < T + L1:
+      self.L1 -= 1
+      return self.seq[-(self.N+1)]
+    elif T + L1 <= rnd < T + L1 + L2:
+      self.L2 -= 1
+      return self.seq[-(self.N-1)]
+
+    self.D -= 1
+    return self.random_distractor()
+
+  def random_distractor(self):
+    pass
\ No newline at end of file