All from same plant. They taste bitter inside. Could they be immature Watermelon / Cucumber ...or something else? Sorry, don't have a picture of the plant.
SOLVED: Roof planter mystery
Thank You both, for your time !
I did think at first it was the Sour Cucumber, because the first fruit I found a few months back wasn't bitter but sour. Now after finding this new batch all tasting bitter & matching it with size, leaf & red color, I'm pretty sure it's Ivy Gourd. Now, I'll go find some recipes.