This is the first time I've had a four year old tell me he is writing a book. I tickled me to see him with his pencil 'writing' away on the blank pages of a bound book. It so happens he is making treasure maps. I don't know if he hides something before he starts his map, but they are clever and do lead to some type of 'prize'.
Oliver is also the one who told me that seagulls (we were watching one at the lake while swinging together) don't eat fish, when I told them the gull had just dived for a fish. I asked him what they did eat and he told me with such authority that they eat insects... I told him he had taught me something new. Then I googled it on my phone and found out that they not only eat fish but even dead fish and sometimes they will even eat from dumpsters anything they can find. So I explained it to him. Later I head him telling his mother that seagulls will eat from dumpsters.