This is a one command block creation for Java 1.13. It creates a rainbow road under your feet. Watch the youtube video for more information.

Command: summon falling_block ~ ~1 ~ {BlockState:{Name:stone},Time:1,Passengers:[{id:falling_block,BlockState:{Name:redstone_block},Time:1,Passengers:[{id:falling_block,BlockState:{Name:activator_rail},Time:1,Passengers:[{id:command_block_minecart,Command:"gamerule commandBlockOutput false"},{id:command_block_minecart,Command:"fill ~2 ~-3 ~-1 ~8 ~-1 ~2 red_terracotta hollow"},{id:command_block_minecart,Command:"fill ~2 ~-2 ~-1 ~8 ~-2 ~2 lime_stained_glass replace red_terracotta"},{id:command_block_minecart,Command:"fill ~3 ~-2 ~ ~7 ~-2 ~1 chain_command_block[facing=east]"},{id:command_block_minecart,Command:"setblock ~7 ~-2 ~1 chain_command_block[facing=west]"},{id:command_block_minecart,Command:"setblock ~7 ~-2 ~ chain_command_block[facing=south]"},{id:command_block_minecart,Command:"setblock ~3 ~-2 ~ repeating_command_block[facing=east]"},{id:command_block_minecart,Command:"data merge block ~7 ~-2 ~1 {auto:1,Command:\"execute at @a run summon armor_stand ~ ~-2 ~-1.5 {Invisible:1b,Invulnerable:1b,NoBasePlate:1b,NoGravity:1b,ArmorItems:[{},{},{},{id:\\\"purple_wool\\\",Count:1b}],HandItems:[{},{}]}\"}"},{id:command_block_minecart,Command:"data merge block ~7 ~-2 ~ {auto:1,Command:\"execute at @a run summon armor_stand ~ ~-2 ~1.5 {Invisible:1b,Invulnerable:1b,NoBasePlate:1b,NoGravity:1b,ArmorItems:[{},{},{},{id:\\\"red_wool\\\",Count:1b}],HandItems:[{},{}]}\"}"},{id:command_block_minecart,Command:"data merge block ~6 ~-2 ~ {auto:1,Command:\"execute at @a run summon armor_stand ~ ~-2 ~-.9 {Invisible:1b,Invulnerable:1b,NoBasePlate:1b,NoGravity:1b,ArmorItems:[{},{},{},{id:\\\"cyan_wool\\\",Count:1b}],HandItems:[{},{}]}\"}"},{id:command_block_minecart,Command:"data merge block ~5 ~-2 ~ {auto:1,Command:\"execute at @a run summon armor_stand ~ ~-2 ~.9 {Invisible:1b,Invulnerable:1b,NoBasePlate:1b,NoGravity:1b,ArmorItems:[{},{},{},{id:\\\"orange_wool\\\",Count:1b}],HandItems:[{},{}]}\"}"},{id:command_block_minecart,Command:"data merge block ~4 ~-2 ~ {auto:1,Command:\"execute at @a run summon armor_stand ~ ~-2 ~-.3 {Invisible:1b,Invulnerable:1b,NoBasePlate:1b,NoGravity:1b,ArmorItems:[{},{},{},{id:\\\"lime_wool\\\",Count:1b}],HandItems:[{},{}]}\"}"},{id:command_block_minecart,Command:"data merge block ~3 ~-2 ~ {auto:1,Command:\"execute at @a run summon armor_stand ~ ~-2 ~.3 {Invisible:1b,Invulnerable:1b,NoBasePlate:1b,NoGravity:1b,ArmorItems:[{},{},{},{id:\\\"yellow_wool\\\",Count:1b}],HandItems:[{},{}]}\"}"},{id:command_block_minecart,Command:"setblock ~ ~ ~1 command_block{Command:\"fill ~ ~-3 ~-1 ~ ~ ~ air\"}"},{id:command_block_minecart,Command:"setblock ~ ~-1 ~1 redstone_block"},{id:command_block_minecart,Command:"kill @e[type=command_block_minecart,distance=..1]"}]}]}]}