input_tensor = Input((100,))
hidden_tensor = Dense(256, activation='relu')(input_tensor)
hidden_tensor = Dense(256, activation='relu')(hidden_tensor)
hidden_tensor = Dense(256, activation='relu')(hidden_tensor)
output_tensor = Concatenate()([input_tensor, hidden_tensor])
output_tensor = Dense(256, activation='relu')(output_tensor)

Visualizing the Loss Landscape of Neural Nets