Flag of the United States of America, according to official government specifications
\documentclass[10pt]{article}
%This is the minimal setup required to render the flag
\usepackage[paperwidth=247cm, paperheight=130cm, top=0cm, bottom=0cm, left=0cm, right=0cm]{geometry}
%Paper width is set to 247cm by 130 cm to match the US Government-specified aspect ratio (1.9:1)
\usepackage{tikz}
%\usepackage[dvipsnames]{xcolor} % Optional unless you want to use colors pre-defined by the xcolor package
% US Government-specified colors for the flag
\definecolor{ssred}{RGB}{179,25,66}
\definecolor{sswhite}{RGB}{255,255,255}
\definecolor{ssblue}{RGB}{10,49,97}
% Other government specifications include:
% Stripe width is 1/13 flag width, here it is 10cm
% Diameter of each star is 4/5 width of each stripe, here it is 8cm
% Width of canton is 2/5 flag width, here it is 98.8cm
% Height of canton is 7/13 flag height, here it is 70cm
%Source: https://eca.state.gov/files/bureau/state_department_u.s._flag_style_guide.pdf
%Created by Senan Sekhon, July 4, 2020
%Happy 4th of July everyone!
\begin{document}
\begin{center} %Optional, but helps to tidy up the layout
\begin{tikzpicture}[scale=1] %Scale must be changed to make the flag fit on letter/A4 paper (scale=1 produces a 247 cm by 130 cm flag)
\clip (-123.5,-65) rectangle (123.5,65); %Optional, crops the flag to the correct size
\draw[-] (-123.5,-65)--(-123.5,65)--(123.5,65)--(123.5,-65)--cycle; %Optional, draws a border around the flag
%Red stripes below the canton (full-length):
\foreach \y in {-65,-45,-25}
\fill[ssred] (-123.5,\y)--(123.5,\y)--(123.5,\y+10)--(-123.5,\y+10)--cycle;
%White stripes below the canton (full-length):
\foreach \y in {-55,-35,-15}
\fill[sswhite] (-123.5,\y)--(123.5,\y)--(123.5,\y+10)--(-123.5,\y+10)--cycle;
%Red stripes beside the canton (3/5-length):
\foreach \y in {-5,15,35,55}
\fill[ssred] (-24.7,\y)--(123.5,\y)--(123.5,\y+10)--(-24.7,\y+10)--cycle;
%White stripes beside the canton (3/5-length):
\foreach \y in {5,25,45}
\fill[sswhite] (-24.7,\y)--(123.5,\y)--(123.5,\y+10)--(-24.7,\y+10)--cycle;
%Canton background:
\fill[ssblue] (-123.5,-5)--(-24.7,-5)--(-24.7,65)--(-123.5,65)--cycle;
%Outer stars (5 rows of 6):
\foreach \x in {-1729/15,-494/5,-247/3,-988/15,-247/5,-494/15}
\foreach \y in {2,16,30,44,58}
\fill[sswhite] (\x,\y+4)--({\x+sqrt(50-22*sqrt(5))},{\y-1+sqrt(5)})--({\x+sqrt(10+2*sqrt(5))},{\y-1+sqrt(5)})--({\x+2*sqrt(5-2*sqrt(5))},{\y+4-2*sqrt(5)})--({\x+sqrt(10-2*sqrt(5))},{\y-1-sqrt(5)})--(\x,{\y-6+2*sqrt(5)})--({\x-sqrt(10-2*sqrt(5))},{\y-1-sqrt(5)})--({\x-2*sqrt(5-2*sqrt(5))},{\y+4-2*sqrt(5)})--({\x-sqrt(10+2*sqrt(5))},{\y-1+sqrt(5)})--({\x-sqrt(50-22*sqrt(5))},{\y-1+sqrt(5)})--cycle;
%Inner stars (4 rows of 5):
\foreach \x in {-3211/30,-2717/30,-741/10,-1729/30,-247/6}
\foreach \y in {9,23,37,51}
\fill[sswhite] (\x,\y+4)--({\x+sqrt(50-22*sqrt(5))},{\y-1+sqrt(5)})--({\x+sqrt(10+2*sqrt(5))},{\y-1+sqrt(5)})--({\x+2*sqrt(5-2*sqrt(5))},{\y+4-2*sqrt(5)})--({\x+sqrt(10-2*sqrt(5))},{\y-1-sqrt(5)})--(\x,{\y-6+2*sqrt(5)})--({\x-sqrt(10-2*sqrt(5))},{\y-1-sqrt(5)})--({\x-2*sqrt(5-2*sqrt(5))},{\y+4-2*sqrt(5)})--({\x-sqrt(10+2*sqrt(5))},{\y-1+sqrt(5)})--({\x-sqrt(50-22*sqrt(5))},{\y-1+sqrt(5)})--cycle;
\end{tikzpicture}
\end{center}
\end{document}