The basis of the drawing is a couple that has three children. The three arrows running next to the clock indicate the life time.
The clock consists of time indications that decrease as time goes up (this is used instead of the numbers on the clock).
The hourglasses are located on the opposite of time. Eg. 12 hours is 100% full so nothing has passed through the hourglass. At three o’clock the hourglass lost 1/3 of the sand so 2/3 is left. At six o’clock ½ has passed, etc.
A couple out of the 7 billion people on earth have three children (male and female symbol). They are two girls (Y) and a boy (X).
The classes to which they belong are indicated by a cross (poor or ordinary people). A bottle and glass which stands for the middle class. Castles for the rich. Whether we are rich, part of the middle class or poor, sooner or later we will die and nothing is taken with us.
A timeline runs underneath the drawing. We are born (illustrated by the black circles). Under the clock we live as our biological clock (heartbeats) and then we die at an unknown age (that is the XXxx).
On the right we have the image of a pyramid representing the pyramid of our age at the time of our death.
We can conclude that up to 70 (due to higher life expectancy today) few people are still dying. At 80 years the majority of the people die and at 90 or more few people die.
In summary: It does not matter whether we are rich, middle class or poor. Everyone dies.