"The grand essentials to happiness in this life are something to do, something to love, and something to hope for."
~George Washington Burnap, [
The sphere and duties of woman : a course of lectures]
I translated this into geometric form - "The Triangle of Happiness"
This one approximates philipma1957's triangle.

The idea of a right-angled “triangle of happiness” is great. It seems to imply that our lives also move forward with three corners: work, love, and hope. These are three important like directions, wherever we turn our eyes, their imprint is there.
If we look at history then we can see that whether it is a great creation or a difficult struggle these three corners of the triangle have worked in the background of our life. Love does not run straight like a curved line of geometry, sometimes high, sometimes low; yet within it lies the continuous beauty of illusion.
Life is also full of ups/downs. We learn to maintain balance as we walk the curved path of rules and regulations. When viewed from a distance, the “triangle of happiness” seems like an engraving on the wall of an ancient temple that has survived time, and is silently teaching: many things are beautifully maintained in the triangular shape.
Finally, this is not just a philosophy point, it is a map of the human heart. Each line tells a story of emotion and the three angles together show what you do in life, who you love, and what you hope for. The path becomes clear.

You've shared a beautiful and insightful metaphor with the "triangle of happiness." It’s a wonderful way to visualize the core elements that shape our lives.
The idea that our existence is guided by these three powerful forces "work, love, and hope" resonates deeply. It's a universal truth that these are often the pillars we lean on, the motivations that drive us, and the elements that give our lives meaning.
Work represents our purpose, our contribution, and the effort we put into creating something.
Love is the connection we feel to others, the relationships that sustain us, and the compassion that fills our hearts.
Hope is the light that guides us through challenges, the belief in a better future, and the engine that fuels our dreams.
Your comparison of this concept to an engraving on an ancient temple wall is especially powerful, suggesting that this isn't a new idea, but a timeless truth that has been part of the human experience for centuries. It's a reminder that even when life's path is curved and full of ups and downs, these three corners provide a stable foundation.