This microfic (my second!) wandered into my head one afternoon while watching the rain showers on the mountains. Apparently I write Don and Leo scenes. I made a couple of references to events in the 2003 TV series, but hopefully don't need to be very familiar with it to understand.
I'll suggest that towards the last few paragraphs that you take your time reading.
Standard Disclaimer (hey, everyone else is doing it): The Mirage Group owns TMNT, not me. Was true yesterday, is true today and will be true tomorrow.
It was early spring yet, but after a long winter cooped up in the lair, everyone was ready for a visit to the farmhouse. As they drove, Don mused about memories. Everywhere that you have been, you leave some part of them behind. And then you revisit them when you return. It wasn't that many winters ago that they were fleeing the city to the farmhouse, with a critically injured Leo. Don had been terrified he would lose a brother that Christmas.
In the fields by the road, Don caught sight of a few crocuses braving the last of the snow to bloom. He smiled, though sadly. They are also a reminder of how fragile life can be. A late frost would kill those flowers.
They had barely been at the farmhouse for half a day before the inevitable clash of brothers who have been living a little too closely together for a little too long. Don escaped through the back door, leaving almost visible ripples in his wake. He stopped on the porch, eyes closed, as if attempting to maintain his composure. He was not even aware that he was not alone, until Leo called to him quietly from the porch swing. "Don? What's wrong?"
Don gave up on being composed and ranted. "It's like they expect me to be able to fix everything in this place instantly. Raph spends more time pointing out things that need to be worked on than actually helping. Mikey just plays ignorant and is conveniently not around when I could have used a hand. I thought that maybe since we left the lair and all those unfinished projects, that I might be able to actually get a little break, like this trip was supposed to be. But I think I'm more harried here than I was back there. If I hear Raph demand that the hot water heater needs attention one more time, I'll..."
Leo broke in gently. "Don." Even with the soft tone, or perhaps because of it, Don trailed off to an uncertain stop. "Breathe, Don." Don did, deeply and almost evenly, and for the first time since leaving the house, noted the scent of damp earth as if just after a rain. "Feeling better?"
"I ... Yes. Just frustrated." Don was suddenly mindful of what memories this place holds for Leo. "What are you doing out here?"
Leo gestured at the sky off in the west. The arc of a rainbow shone out in front of the dark clouds of a passing rainstorm off in the distance. "What do you see?"
"The rainbow? Well, it's an optical effect caused by the dispersion of sunlight through those rain clouds. The light refracts when it first enters the raindrop, then reflects off the back of the drop and finally refracts again when it leaves the drop. Shorter wavelength light is refracted at a greater angle than longer wavelengths, which separates the sunlight into the spectrum of colors. It was Qutb al-Din al-Shirazi, a Persian astronomer, who in the 13th century, first gave a scientifically correct explanation for the formation of a rainbow." Don paused only to take a breath. "Did you know a rainbow does not actually exist at a particular location? That's an illusion depending of the observer's location and the position of the sun.
Leo chuckled amusedly, forestalling any continuation of Don's discourse. "Yes, I suppose that is what you would see." He glanced back at the rainbow. "So a rainbow only exists when someone sees it?"
"Well, not exactly." "Though," Don continued slowly, "you could say that each person sees their own rainbow. The raindrops all reflect and refract the light the same, but only light from some raindrops reach each the observer's eyes. And that depends on where the observer is located; so for an example, you and I see light from a different set of raindrops."
"We each see our own rainbow", Leo murmured, half to himself. "Let me ask you another question then." Leo returned his focus back on Don. "What do you think Raph or Mikey sees?"
"Well, I assume ...", Don trailed off. "Actually, I don't know. I suppose I would have to ask them." Don was silent for a time, before he asked, "What do you see?"
Without looking away from the sky, Leo answered. "Something that should be appreciated for what it is. Enjoyed for however long it lasts. Then let go when it is gone."
Don sat down on the other end of the porch swing. The rain moved on and the rainbow faded. But it was well past sunset before either of them left.