When Cillian next asked for a drink, he was offered the following choices (see table below)

Later that afternoon he shouted "yellow cup". He poured out the water in the yellow cup and the juice in the blue cup was offered instead. Both were replaced and he chose the blue cup.

Since then he has been using ordinary cups and tumblers. We could have thrown his yellow cup away and worked through the tantrums. However this reinforced, less rigid behaviour, and encouraged more appropriate behaviour at meal times and in other peoples houses.

Yellow Cup

Blue Cup

Leaf Cup

Results

1 water

Blackberry Juice

Orange Juice

Sipped all 3 twice, chose leaf cup

2 water

Blackberry Juice

Milk

Sipped all 3 chose leaf cup

3 water

Diet Pepsi

Blackberry juice

Sipped all 3 chose blue cup

4 water

Blackberry Juice

Diet Pepsi

Looked at them all, said leaf and took it.