Several lights, flashing green, red and blue, appear over Banja Luka at night, later on a whole "fleet reappears."Note: I know the exact time and events because I recorded it all on my phone's notes.At 0:44 in the morning my friend sent me a message about how he just saw a odd light that changes color from time to time on the sky and is not moving. I went to my balcony, and noticed it on my left side, glowing green and would sometimes become red.The object moved slightly right and I noticed i see it better and brighter if i don't look directly into it.At 1:02 AM i noticed another light above the first one, and they slightly faded out and would only flash up for a milisecond in perfect synchronization with each other.At 1:04 AM, I noticed there are at least 4 of them making a accurate rhombus on my left, and we're mostly green.1:08 AM, I accidentaly aimed my phone's lighted up screen (i was communicating with my friend about this) at the lower light of the now not moving rhombus. The (green) light instantly started flashing red extremely quickly. I moved the phone away and it stopped. I repeated this 3 times, always the same result. (So i assume they have light perception similiar to us) Soon after i tried pointing my phone's light at the (now red) light, it started to slowly move out of the rhombus and started getting closer and closer to my home (or in this case, 4 floor residential building). I could clearly see a small, pale red light always going behind the bigger red light that was coming closer to me.Slowly, at 1:20 AM it completely went out of my sight because of my balcony's roof. The other 3 we're somehow harder to see, usually white likr they are trying to pretent they are stars, but very bright and would become red for a few seconds sometimes.1:21 AM, the 3 lights dissappeared, and the one that was hidden from my sight by my balcony roof could be seen again at my right, slowly changing from red to white and sometimes green.1:25 AM, it is still right of me, slowly moving left and made a blue flash of light.Until 1:48 AM the random activity continued and the light would mostly change colors every few seconds to a minute. It suddenly flashed a dim white, red then white again light.There we're a few small flashes later on, but nothing noteworthy.At 2:22 AM the lights dissappeared. I decided to stay for some time, see if anything happens.Finally, at 3:04, the biggest event happened. A bit left of me, at least 7 lights appeared and slowly spread out. A several more light appeared at the same spot and also spread out covering a huge part of the sky. They rearranged into a odd position, making 3 lines consisting of 3 lights, one line left, two in the center, and above and right of them making random shapes. They didn't move later on, and we're mostly just green, occasionaly flashing red.Note: I tried to photograph the object, but my phones camera was unable to "detect" any of the lights for some reason, possibly because of tge distance.